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Thiazide Diuretics

Thiazide Thiazide Heterocyclic compounds with sulfur and nitrogen in the ring. This term commonly refers to the benzothiadiazines that inhibit sodium-potassium-chloride symporters and are used as diuretics. Hyponatremia and thiazide-like diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication make up a group of highly important antihypertensive agents, with some drugs being 1st-line agents. The class includes hydrochlorothiazide, chlorothiazide Chlorothiazide A thiazide diuretic with actions and uses similar to those of hydrochlorothiazide. Hypertension Drugs, chlorthalidone, indapamide Indapamide A benzamide-sulfonamide-indole derived diuretic that functions by inhibiting sodium chloride symporters. Hypertension Drugs, and metolazone Metolazone A quinazoline-sulfonamide derived diuretic that functions by inhibiting sodium chloride symporters. Hypertension Drugs. These drugs block sodium Sodium A member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23. Hyponatremia reabsorption in the distal convoluted tubule Distal convoluted tubule The portion of renal tubule that begins from the enlarged segment of the ascending limb of the loop of henle. It reenters the kidney cortex and forms the convoluted segments of the distal tubule. Gitelman Syndrome of the kidney by inhibiting the sodium-chloride cotransporter. As a result, the increased sodium Sodium A member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23. Hyponatremia excretion causes secondary water excretion because water follows the sodium Sodium A member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23. Hyponatremia. In addition to increasing sodium Sodium A member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23. Hyponatremia and water excretion, thiazide Thiazide Heterocyclic compounds with sulfur and nitrogen in the ring. This term commonly refers to the benzothiadiazines that inhibit sodium-potassium-chloride symporters and are used as diuretics. Hyponatremia diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication also cause the excretion of chloride Chloride Inorganic compounds derived from hydrochloric acid that contain the Cl- ion. Electrolytes, potassium Potassium An element in the alkali group of metals with an atomic symbol k, atomic number 19, and atomic weight 39. 10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the water-electrolyte balance. Hyperkalemia, magnesium Magnesium A metallic element that has the atomic symbol mg, atomic number 12, and atomic weight 24. 31. It is important for the activity of many enzymes, especially those involved in oxidative phosphorylation. Electrolytes, and protons (H+).

Last updated: Sep 1, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Overview

Overview of antihypertensive agents

Table: Drugs used to treat hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
Location of action Class Subclasses
Renal drugs Drugs affecting the RAAS RAAS A blood pressure regulating system of interacting components that include renin; angiotensinogen; angiotensin converting enzyme; angiotensin i; angiotensin ii; and angiotensinase. Renin, an enzyme produced in the kidney, acts on angiotensinogen, an alpha-2 globulin produced by the liver, forming angiotensin I. Angiotensin-converting enzyme, contained in the lung, acts on angiotensin I in the plasma converting it to angiotensin II, an extremely powerful vasoconstrictor. Angiotensin II causes contraction of the arteriolar and renal vascular smooth muscle, leading to retention of salt and water in the kidney and increased arterial blood pressure. In addition, angiotensin II stimulates the release of aldosterone from the adrenal cortex, which in turn also increases salt and water retention in the kidney. Angiotensin-converting enzyme also breaks down bradykinin, a powerful vasodilator and component of the kallikrein-kinin system. Adrenal Hormones
  • ACEis ACEIs A class of drugs whose main indications are the treatment of hypertension and heart failure. They exert their hemodynamic effect mainly by inhibiting the renin-angiotensin system. They also modulate sympathetic nervous system activity and increase prostaglandin synthesis. They cause mainly vasodilation and mild natriuresis without affecting heart rate and contractility. Heart Failure and Angina Medication
  • ARBs ARBs Agents that antagonize angiotensin receptors. Many drugs in this class specifically target the angiotensin type 1 receptor. Heart Failure and Angina Medication
  • Direct renin Renin A highly specific (leu-leu) endopeptidase that generates angiotensin I from its precursor angiotensinogen, leading to a cascade of reactions which elevate blood pressure and increase sodium retention by the kidney in the renin-angiotensin system. Renal Sodium and Water Regulation inhibitors
Diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication
  • Thiazide Thiazide Heterocyclic compounds with sulfur and nitrogen in the ring. This term commonly refers to the benzothiadiazines that inhibit sodium-potassium-chloride symporters and are used as diuretics. Hyponatremia diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication
  • Loop diuretics Loop diuretics Loop diuretics are a group of diuretic medications primarily used to treat fluid overload in edematous conditions such as heart failure and cirrhosis. Loop diuretics also treat hypertension, but not as a 1st-line agent. Loop Diuretics
  • Potassium-sparing diuretics Potassium-sparing diuretics Potassium-sparing diuretics are medications that act in the principal cells in the collecting ducts to induce diuresis that does not result in excretion of potassium. These diuretics include 2 subclasses: sodium channel blockers and aldosterone antagonists. Potassium-sparing Diuretics
Extrarenal drugs Direct vasodilators Vasodilators Drugs used to cause dilation of the blood vessels. Thromboangiitis Obliterans (Buerger’s Disease)
  • Calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes channel blockers
  • Potassium Potassium An element in the alkali group of metals with an atomic symbol k, atomic number 19, and atomic weight 39. 10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the water-electrolyte balance. Hyperkalemia channel openers
  • Nitrodilators
  • Endothelin antagonists
Agents acting via the sympathetic nervous system Nervous system The nervous system is a small and complex system that consists of an intricate network of neural cells (or neurons) and even more glial cells (for support and insulation). It is divided according to its anatomical components as well as its functional characteristics. The brain and spinal cord are referred to as the central nervous system, and the branches of nerves from these structures are referred to as the peripheral nervous system. Nervous System: Anatomy, Structure, and Classification
  • Drugs affecting CNS sympathetic outflow (e.g., clonidine Clonidine An imidazoline sympatholytic agent that stimulates alpha-2 adrenergic receptors and central imidazoline receptors. It is commonly used in the management of hypertension. Sympathomimetic Drugs)
  • Drugs affecting the ganglia (e.g., hexamethonium)
  • Drugs affecting the nerve terminals (e.g., guanethidine, reserpine)
  • Drugs affecting the α and β receptors Receptors Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors

Drugs in the thiazide Thiazide Heterocyclic compounds with sulfur and nitrogen in the ring. This term commonly refers to the benzothiadiazines that inhibit sodium-potassium-chloride symporters and are used as diuretics. Hyponatremia class

Drugs in this class include: 

  • Hydrochlorothiazide (HCTZ; prototypical drug in this class)
  • Chlorothiazide Chlorothiazide A thiazide diuretic with actions and uses similar to those of hydrochlorothiazide. Hypertension Drugs 
  • Chlorthalidone (1st-line agent in the treatment of hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension)
  • Indapamide Indapamide A benzamide-sulfonamide-indole derived diuretic that functions by inhibiting sodium chloride symporters. Hypertension Drugs
  • Metolazone Metolazone A quinazoline-sulfonamide derived diuretic that functions by inhibiting sodium chloride symporters. Hypertension Drugs

Chemistry and Pharmacodynamics

Chemical structure

The chemical structure for HCTZ:

  • Molecular formula: C7H8ClN3O4S2
  • A benzothiadiazine that is 3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxide with substitutions of:
    • A chloro group at position 6 
    • A sulfonamide Sulfonamide The sulfonamides are a class of antimicrobial drugs inhibiting folic acid synthesize in pathogens. The prototypical drug in the class is sulfamethoxazole. Although not technically sulfonamides, trimethoprim, dapsone, and pyrimethamine are also important antimicrobial agents inhibiting folic acid synthesis. The agents are often combined with sulfonamides, resulting in a synergistic effect. Sulfonamides and Trimethoprim at position 7
Hydrochlorothiazide

Skeletal formula of hydrochlorothiazide

Image: “Hydrochlorothiazide” by Yikrazuul. License: Public Domain

Mechanism of action (MOA)

  • Primary MOA: ↓ reabsorption of NaCl through the inhibition of the Na+/Cl cotransporter in the distal convoluted tubule Distal convoluted tubule The portion of renal tubule that begins from the enlarged segment of the ascending limb of the loop of henle. It reenters the kidney cortex and forms the convoluted segments of the distal tubule. Gitelman Syndrome (DCT):
    • With this channel blocked → ↓ Na+ reabsorption
    • Water always follows Na+:
      • Water stays with Na+ in the tubules (rather than being reabsorbed).
      • Diuresis results from the osmotic effect of Na+.
    • Diuresis → ↓ plasma Plasma The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation. Transfusion Products volume → ↓ BP:
      • Initially causes a transient ↑ in the RAAS RAAS A blood pressure regulating system of interacting components that include renin; angiotensinogen; angiotensin converting enzyme; angiotensin i; angiotensin ii; and angiotensinase. Renin, an enzyme produced in the kidney, acts on angiotensinogen, an alpha-2 globulin produced by the liver, forming angiotensin I. Angiotensin-converting enzyme, contained in the lung, acts on angiotensin I in the plasma converting it to angiotensin II, an extremely powerful vasoconstrictor. Angiotensin II causes contraction of the arteriolar and renal vascular smooth muscle, leading to retention of salt and water in the kidney and increased arterial blood pressure. In addition, angiotensin II stimulates the release of aldosterone from the adrenal cortex, which in turn also increases salt and water retention in the kidney. Angiotensin-converting enzyme also breaks down bradykinin, a powerful vasodilator and component of the kallikrein-kinin system. Adrenal Hormones and sympathetic tone to compensate for ↓ BP and cardiac output Cardiac output The volume of blood passing through the heart per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with stroke volume (volume per beat). Cardiac Mechanics.
      • Transient ↑ in the RAAS RAAS A blood pressure regulating system of interacting components that include renin; angiotensinogen; angiotensin converting enzyme; angiotensin i; angiotensin ii; and angiotensinase. Renin, an enzyme produced in the kidney, acts on angiotensinogen, an alpha-2 globulin produced by the liver, forming angiotensin I. Angiotensin-converting enzyme, contained in the lung, acts on angiotensin I in the plasma converting it to angiotensin II, an extremely powerful vasoconstrictor. Angiotensin II causes contraction of the arteriolar and renal vascular smooth muscle, leading to retention of salt and water in the kidney and increased arterial blood pressure. In addition, angiotensin II stimulates the release of aldosterone from the adrenal cortex, which in turn also increases salt and water retention in the kidney. Angiotensin-converting enzyme also breaks down bradykinin, a powerful vasodilator and component of the kallikrein-kinin system. Adrenal Hormones explains why there is a synergistic effect between thiazides and ACEis ACEIs A class of drugs whose main indications are the treatment of hypertension and heart failure. They exert their hemodynamic effect mainly by inhibiting the renin-angiotensin system. They also modulate sympathetic nervous system activity and increase prostaglandin synthesis. They cause mainly vasodilation and mild natriuresis without affecting heart rate and contractility. Heart Failure and Angina Medication/ ARBs ARBs Agents that antagonize angiotensin receptors. Many drugs in this class specifically target the angiotensin type 1 receptor. Heart Failure and Angina Medication.
    • There is also a modest ↑ in vasodilation Vasodilation The physiological widening of blood vessels by relaxing the underlying vascular smooth muscle. Pulmonary Hypertension Drugs via an unclear mechanism.
  • Thiazide Thiazide Heterocyclic compounds with sulfur and nitrogen in the ring. This term commonly refers to the benzothiadiazines that inhibit sodium-potassium-chloride symporters and are used as diuretics. Hyponatremia use results in:
    • ↑ Excretion of Na+, Cl, K+, and water 
    • ↑ Reabsorption of Ca CA Condylomata acuminata are a clinical manifestation of genital HPV infection. Condylomata acuminata are described as raised, pearly, flesh-colored, papular, cauliflower-like lesions seen in the anogenital region that may cause itching, pain, or bleeding. Condylomata Acuminata (Genital Warts)2+
      • ↑ Na+ excretion → ↓ cellular Na+ levels → 
      • ↑ Compensatory exchange of Ca CA Condylomata acuminata are a clinical manifestation of genital HPV infection. Condylomata acuminata are described as raised, pearly, flesh-colored, papular, cauliflower-like lesions seen in the anogenital region that may cause itching, pain, or bleeding. Condylomata Acuminata (Genital Warts)2+ for Na+ (via the basolateral Na+/ Ca CA Condylomata acuminata are a clinical manifestation of genital HPV infection. Condylomata acuminata are described as raised, pearly, flesh-colored, papular, cauliflower-like lesions seen in the anogenital region that may cause itching, pain, or bleeding. Condylomata Acuminata (Genital Warts)2+ exchanger)
  • Development of hypokalemia Hypokalemia Hypokalemia is defined as plasma potassium (K+) concentration < 3.5 mEq/L. Homeostatic mechanisms maintain plasma concentration between 3.5-5.2 mEq/L despite marked variation in dietary intake. Hypokalemia can be due to renal losses, GI losses, transcellular shifts, or poor dietary intake. Hypokalemia:
    • ↓ Na+ reabsorption in the DCT → 
    • ↑ Na+ delivered to the collecting ducts (CDs) → 
    • Stimulates ↑ aldosterone Aldosterone A hormone secreted by the adrenal cortex that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium. Hyperkalemia release Release Release of a virus from the host cell following virus assembly and maturation. Egress can occur by host cell lysis, exocytosis, or budding through the plasma membrane. Virology
    • Aldosterone Aldosterone A hormone secreted by the adrenal cortex that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium. Hyperkalemia stimulates Na+/K+ exchanger to ↑ Na+ reabsorption and excrete K+ hypokalemia Hypokalemia Hypokalemia is defined as plasma potassium (K+) concentration < 3.5 mEq/L. Homeostatic mechanisms maintain plasma concentration between 3.5-5.2 mEq/L despite marked variation in dietary intake. Hypokalemia can be due to renal losses, GI losses, transcellular shifts, or poor dietary intake. Hypokalemia
  • Development of a metabolic alkalosis Alkalosis A pathological condition that removes acid or adds base to the body fluids. Respiratory Alkalosis:
    • ↑ K+ excretion in the CD → 
    • Aldosterone-stimulated ↑ in K+/H+ exchanger → 
    • Reabsorbs some of the extra K+ in the tubule in exchange for H+ (which is excreted) → metabolic alkalosis Alkalosis A pathological condition that removes acid or adds base to the body fluids. Respiratory Alkalosis via H+ loss
Thiazide diuretics acting

Thiazide Thiazide Heterocyclic compounds with sulfur and nitrogen in the ring. This term commonly refers to the benzothiadiazines that inhibit sodium-potassium-chloride symporters and are used as diuretics. Hyponatremia diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication acting on the Na/Cl cotransporter

Image by Lecturio. License: CC BY-NC-SA 4.0

Pharmacokinetics

Table: Pharmacokinetics Pharmacokinetics Pharmacokinetics is the science that analyzes how the human body interacts with a drug. Pharmacokinetics examines how the drug is absorbed, distributed, metabolized, and excreted by the body. Pharmacokinetics and Pharmacodynamics of thiazide Thiazide Heterocyclic compounds with sulfur and nitrogen in the ring. This term commonly refers to the benzothiadiazines that inhibit sodium-potassium-chloride symporters and are used as diuretics. Hyponatremia diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication
Drug Absorption Absorption Absorption involves the uptake of nutrient molecules and their transfer from the lumen of the GI tract across the enterocytes and into the interstitial space, where they can be taken up in the venous or lymphatic circulation. Digestion and Absorption Distribution Metabolism Excretion
HCTZ
  • Vd: 3.6–7.8 L/kg
  • Protein binding 40%–68%
Not metabolized
Chlorothiazide Chlorothiazide A thiazide diuretic with actions and uses similar to those of hydrochlorothiazide. Hypertension Drugs
  • Poor oral absorption Absorption Absorption involves the uptake of nutrient molecules and their transfer from the lumen of the GI tract across the enterocytes and into the interstitial space, where they can be taken up in the venous or lymphatic circulation. Digestion and Absorption
  • Peak effect: 30 minutes IV
Distributed throughout the extracellular space Not metabolized
Chlorthalidone Peak effect 2–6 hours
  • Vd: 3–13 L/kg
  • Protein binding: 75%
Hepatic
Indapamide Indapamide A benzamide-sulfonamide-indole derived diuretic that functions by inhibiting sodium chloride symporters. Hypertension Drugs
  • Rapid and complete absorption Absorption Absorption involves the uptake of nutrient molecules and their transfer from the lumen of the GI tract across the enterocytes and into the interstitial space, where they can be taken up in the venous or lymphatic circulation. Digestion and Absorption
  • Peak effect: 2 hours
  • Vd: 25 L
  • Protein binding: approximately 75%
Extensive hepatic metabolism
  • Urine: 75%
  • Feces: 25%
Metolazone Metolazone A quinazoline-sulfonamide derived diuretic that functions by inhibiting sodium chloride symporters. Hypertension Drugs Onset of action: 1 hour
  • Vd: 113 L
  • Protein binding: 95%
Not metabolized Urine
HCTZ: hydrochlorothiazide
Vd: volume of distribution

Indications

Indications

Most thiazide Thiazide Heterocyclic compounds with sulfur and nitrogen in the ring. This term commonly refers to the benzothiadiazines that inhibit sodium-potassium-chloride symporters and are used as diuretics. Hyponatremia diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication share similar indications, including:

  • Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
  • As an adjunctive therapy for edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema in the following conditions:
    • Heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)
    • Hepatic cirrhosis Cirrhosis Cirrhosis is a late stage of hepatic parenchymal necrosis and scarring (fibrosis) most commonly due to hepatitis C infection and alcoholic liver disease. Patients may present with jaundice, ascites, and hepatosplenomegaly. Cirrhosis can also cause complications such as hepatic encephalopathy, portal hypertension, portal vein thrombosis, and hepatorenal syndrome. Cirrhosis resulting in ascites Ascites Ascites is the pathologic accumulation of fluid within the peritoneal cavity that occurs due to an osmotic and/or hydrostatic pressure imbalance secondary to portal hypertension (cirrhosis, heart failure) or non-portal hypertension (hypoalbuminemia, malignancy, infection). Ascites
    • Mild to moderate renal dysfunction ( CKD CKD Chronic kidney disease (CKD) is kidney impairment that lasts for ≥ 3 months, implying that it is irreversible. Hypertension and diabetes are the most common causes; however, there are a multitude of other etiologies. In the early to moderate stages, CKD is usually asymptomatic and is primarily diagnosed by laboratory abnormalities. Chronic Kidney Disease stages 1–3): 
      • Includes CKD CKD Chronic kidney disease (CKD) is kidney impairment that lasts for ≥ 3 months, implying that it is irreversible. Hypertension and diabetes are the most common causes; however, there are a multitude of other etiologies. In the early to moderate stages, CKD is usually asymptomatic and is primarily diagnosed by laboratory abnormalities. Chronic Kidney Disease due to nephrotic syndrome Nephrotic syndrome Nephrotic syndrome is characterized by severe proteinuria, hypoalbuminemia, and peripheral edema. In contrast, the nephritic syndromes present with hematuria, variable loss of renal function, and hypertension, although there is sometimes overlap of > 1 glomerular disease in the same individual. Nephrotic Syndrome, glomerulonephritis, chronic renal failure Renal failure Conditions in which the kidneys perform below the normal level in the ability to remove wastes, concentrate urine, and maintain electrolyte balance; blood pressure; and calcium metabolism. Renal insufficiency can be classified by the degree of kidney damage (as measured by the level of proteinuria) and reduction in glomerular filtration rate. Crush Syndrome
      • Note: Thiazides are relatively contraindicated in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with anuria Anuria Absence of urine formation. It is usually associated with complete bilateral ureteral (ureter) obstruction, complete lower urinary tract obstruction, or unilateral ureteral obstruction when a solitary kidney is present. Acute Kidney Injury/severe renal failure Renal failure Conditions in which the kidneys perform below the normal level in the ability to remove wastes, concentrate urine, and maintain electrolyte balance; blood pressure; and calcium metabolism. Renal insufficiency can be classified by the degree of kidney damage (as measured by the level of proteinuria) and reduction in glomerular filtration rate. Crush Syndrome ( CKD CKD Chronic kidney disease (CKD) is kidney impairment that lasts for ≥ 3 months, implying that it is irreversible. Hypertension and diabetes are the most common causes; however, there are a multitude of other etiologies. In the early to moderate stages, CKD is usually asymptomatic and is primarily diagnosed by laboratory abnormalities. Chronic Kidney Disease stages 4 and 5).
    • Corticosteroid use
    • Estrogen Estrogen Compounds that interact with estrogen receptors in target tissues to bring about the effects similar to those of estradiol. Estrogens stimulate the female reproductive organs, and the development of secondary female sex characteristics. Estrogenic chemicals include natural, synthetic, steroidal, or non-steroidal compounds. Ovaries: Anatomy therapy
  • Off-label uses: 
    • Hypercalciuria Hypercalciuria Excretion of abnormally high level of calcium in the urine, greater than 4 mg/kg/day. Nephrolithiasis 
    • Diabetes insipidus Diabetes Insipidus Diabetes insipidus (DI) is a condition in which the kidneys are unable to concentrate urine. There are 2 subforms of DI: central DI (CDI) and nephrogenic DI (NDI). Both conditions result in the kidneys being unable to concentrate urine, leading to polyuria, nocturia, and polydipsia. Diabetes Insipidus 

Clinical pearls

  • All patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship should be monitored for BP, creatinine, Na+, and K+.
  • Chlorthalidone and indapamide Indapamide A benzamide-sulfonamide-indole derived diuretic that functions by inhibiting sodium chloride symporters. Hypertension Drugs:
    • 1st-line agents for monotherapy when treating hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
    • 1.5–2× as potent and longer half-life Half-Life The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity. Pharmacokinetics and Pharmacodynamics than HCTZ 
    • ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Heart attack Mi is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction Trial) showed reduction in cardiovascular events (has the most evidence of all the thiazides).
    • May have ↑ side effects and risk of hypokalemia Hypokalemia Hypokalemia is defined as plasma potassium (K+) concentration < 3.5 mEq/L. Homeostatic mechanisms maintain plasma concentration between 3.5-5.2 mEq/L despite marked variation in dietary intake. Hypokalemia can be due to renal losses, GI losses, transcellular shifts, or poor dietary intake. Hypokalemia
  • HCTZ:
    • Commonly used as 1st-line agent for hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension, though less effective than chlorthalidone or indapamide Indapamide A benzamide-sulfonamide-indole derived diuretic that functions by inhibiting sodium chloride symporters. Hypertension Drugs
    • Comes in combination pills with ACEis ACEIs A class of drugs whose main indications are the treatment of hypertension and heart failure. They exert their hemodynamic effect mainly by inhibiting the renin-angiotensin system. They also modulate sympathetic nervous system activity and increase prostaglandin synthesis. They cause mainly vasodilation and mild natriuresis without affecting heart rate and contractility. Heart Failure and Angina Medication, ARBs ARBs Agents that antagonize angiotensin receptors. Many drugs in this class specifically target the angiotensin type 1 receptor. Heart Failure and Angina Medication, and/or calcium-channel blockers Calcium-Channel Blockers A class of drugs that act by selective inhibition of calcium influx through cellular membranes. Heart Failure and Angina Medication
    • Not as effective with creatinine clearance Creatinine clearance Kidney Function Tests < 30 ml/min
  • Metolazone Metolazone A quinazoline-sulfonamide derived diuretic that functions by inhibiting sodium chloride symporters. Hypertension Drugs:
    • May be more effective than other thiazides with CrCl < 30 ml/min
    • Often combined with other diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication

Adverse Effects and Contraindications

Adverse effects

Table: Adverse effects of thiazide Thiazide Heterocyclic compounds with sulfur and nitrogen in the ring. This term commonly refers to the benzothiadiazines that inhibit sodium-potassium-chloride symporters and are used as diuretics. Hyponatremia diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication
Thiazide Thiazide Heterocyclic compounds with sulfur and nitrogen in the ring. This term commonly refers to the benzothiadiazines that inhibit sodium-potassium-chloride symporters and are used as diuretics. Hyponatremia adverse effects Mechanism Management
Hypokalemia Hypokalemia Hypokalemia is defined as plasma potassium (K+) concentration < 3.5 mEq/L. Homeostatic mechanisms maintain plasma concentration between 3.5-5.2 mEq/L despite marked variation in dietary intake. Hypokalemia can be due to renal losses, GI losses, transcellular shifts, or poor dietary intake. Hypokalemia ↑ Urinary Na+ causes ↑ K+ exchange in the CD → ↑ K+ excretion ↑ Dietary intake of K+ or supplementation
Hyponatremia Hyponatremia Hyponatremia is defined as a decreased serum sodium (sNa+) concentration less than 135 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled via antidiuretic hormone (ADH) release from the hypothalamus and by the thirst mechanism. Hyponatremia and hypovolemia Hypovolemia Sepsis in Children ↓ Na+ reabsorption results in ↓ serum Na+; water follows Na+, potentially leading to hypovolemia Hypovolemia Sepsis in Children (most likely to occur in the 1st few weeks of therapy)
Metabolic alkalosis Alkalosis A pathological condition that removes acid or adds base to the body fluids. Respiratory Alkalosis ↑ Exchange of K+ for H+ ions in the CD Potassium Potassium An element in the alkali group of metals with an atomic symbol k, atomic number 19, and atomic weight 39. 10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the water-electrolyte balance. Hyperkalemia supplementation and/or lower dose/switch agents
Hypomagnesemia Hypomagnesemia A nutritional condition produced by a deficiency of magnesium in the diet, characterized by anorexia, nausea, vomiting, lethargy, and weakness. Symptoms are paresthesias, muscle cramps, irritability, decreased attention span, and mental confusion, possibly requiring months to appear. Deficiency of body magnesium can exist even when serum values are normal. In addition, magnesium deficiency may be organ-selective, since certain tissues become deficient before others. Electrolytes Not fully elucidated Mg2+ supplementation
Hyperuricemia Hyperuricemia Excessive uric acid or urate in blood as defined by its solubility in plasma at 37 degrees c; greater than 0. 42 mmol per liter (7. 0 mg/dl) in men or 0. 36 mmol per liter (6. 0 mg/dl) in women. Gout Thiazides ↑ urate reabsorption Avoid thiazides in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with untreated gout Gout Gout is a heterogeneous metabolic disease associated with elevated serum uric acid levels (> 6.8 mg/dL) and abnormal deposits of monosodium urate in tissues. The condition is often familial and is initially characterized by painful, recurring, and usually monoarticular acute arthritis, or “gout flare,” followed later by chronic deforming arthritis. Gout or at high risk for gout Gout Gout is a heterogeneous metabolic disease associated with elevated serum uric acid levels (> 6.8 mg/dL) and abnormal deposits of monosodium urate in tissues. The condition is often familial and is initially characterized by painful, recurring, and usually monoarticular acute arthritis, or “gout flare,” followed later by chronic deforming arthritis. Gout.
Hypercalcemia Hypercalcemia Hypercalcemia (serum calcium > 10.5 mg/dL) can result from various conditions, the majority of which are due to hyperparathyroidism and malignancy. Other causes include disorders leading to vitamin D elevation, granulomatous diseases, and the use of certain pharmacological agents. Symptoms vary depending on calcium levels and the onset of hypercalcemia. Hypercalcemia Thiazide-induced ↑ of Ca CA Condylomata acuminata are a clinical manifestation of genital HPV infection. Condylomata acuminata are described as raised, pearly, flesh-colored, papular, cauliflower-like lesions seen in the anogenital region that may cause itching, pain, or bleeding. Condylomata Acuminata (Genital Warts)2+ reabsorption Typically inconsequential in absence of CKD CKD Chronic kidney disease (CKD) is kidney impairment that lasts for ≥ 3 months, implying that it is irreversible. Hypertension and diabetes are the most common causes; however, there are a multitude of other etiologies. In the early to moderate stages, CKD is usually asymptomatic and is primarily diagnosed by laboratory abnormalities. Chronic Kidney Disease or hyperparathyroidism Hyperparathyroidism Hyperparathyroidism is a condition associated with elevated blood levels of parathyroid hormone (PTH). Depending on the pathogenesis of this condition, hyperparathyroidism can be defined as primary, secondary or tertiary. Hyperparathyroidism
Hyperglycemia Hyperglycemia Abnormally high blood glucose level. Diabetes Mellitus
  • ↓ K+ hyperpolarization Hyperpolarization Membrane Potential in pancreatic β cells → ↓ insulin Insulin Insulin is a peptide hormone that is produced by the beta cells of the pancreas. Insulin plays a role in metabolic functions such as glucose uptake, glycolysis, glycogenesis, lipogenesis, and protein synthesis. Exogenous insulin may be needed for individuals with diabetes mellitus, in whom there is a deficiency in endogenous insulin or increased insulin resistance. Insulin secretion Secretion Coagulation Studies
  • Seen in higher doses in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with underlying diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
  • Consider alternative agents in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus.
  • Thiazide Thiazide Heterocyclic compounds with sulfur and nitrogen in the ring. This term commonly refers to the benzothiadiazines that inhibit sodium-potassium-chloride symporters and are used as diuretics. Hyponatremia dose
  • Correct hypokalemia Hypokalemia Hypokalemia is defined as plasma potassium (K+) concentration < 3.5 mEq/L. Homeostatic mechanisms maintain plasma concentration between 3.5-5.2 mEq/L despite marked variation in dietary intake. Hypokalemia can be due to renal losses, GI losses, transcellular shifts, or poor dietary intake. Hypokalemia.
  • Treat diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus.
Dyslipidemia
  • Not fully elucidated
  • Risk is ↓ with indapamide Indapamide A benzamide-sulfonamide-indole derived diuretic that functions by inhibiting sodium chloride symporters. Hypertension Drugs.
  • Lipid monitoring
  • Lipid-lowering diet and medications
Photosensitivity Photosensitivity Tetracyclines Not fully elucidated Wear sunscreen Sunscreen Chemical or physical agents that protect the skin from sunburn and erythema by absorbing or blocking ultraviolet radiation. Melanoma and protective clothing.
Hypersensitivity Underlying sulfonamide Sulfonamide The sulfonamides are a class of antimicrobial drugs inhibiting folic acid synthesize in pathogens. The prototypical drug in the class is sulfamethoxazole. Although not technically sulfonamides, trimethoprim, dapsone, and pyrimethamine are also important antimicrobial agents inhibiting folic acid synthesis. The agents are often combined with sulfonamides, resulting in a synergistic effect. Sulfonamides and Trimethoprim allergy Allergy An abnormal adaptive immune response that may or may not involve antigen-specific IgE Type I Hypersensitivity Reaction Avoid thiazides.

Contraindications Contraindications A condition or factor associated with a recipient that makes the use of a drug, procedure, or physical agent improper or inadvisable. Contraindications may be absolute (life threatening) or relative (higher risk of complications in which benefits may outweigh risks). Noninvasive Ventilation

  • Thiazide Thiazide Heterocyclic compounds with sulfur and nitrogen in the ring. This term commonly refers to the benzothiadiazines that inhibit sodium-potassium-chloride symporters and are used as diuretics. Hyponatremia contraindications Contraindications A condition or factor associated with a recipient that makes the use of a drug, procedure, or physical agent improper or inadvisable. Contraindications may be absolute (life threatening) or relative (higher risk of complications in which benefits may outweigh risks). Noninvasive Ventilation:
    • Hypersensitivity reactions
    • Anuria Anuria Absence of urine formation. It is usually associated with complete bilateral ureteral (ureter) obstruction, complete lower urinary tract obstruction, or unilateral ureteral obstruction when a solitary kidney is present. Acute Kidney Injury and/or renal failure Renal failure Conditions in which the kidneys perform below the normal level in the ability to remove wastes, concentrate urine, and maintain electrolyte balance; blood pressure; and calcium metabolism. Renal insufficiency can be classified by the degree of kidney damage (as measured by the level of proteinuria) and reduction in glomerular filtration rate. Crush Syndrome
    • Hypotension Hypotension Hypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension
    • Hypokalemia Hypokalemia Hypokalemia is defined as plasma potassium (K+) concentration < 3.5 mEq/L. Homeostatic mechanisms maintain plasma concentration between 3.5-5.2 mEq/L despite marked variation in dietary intake. Hypokalemia can be due to renal losses, GI losses, transcellular shifts, or poor dietary intake. Hypokalemia
    • Allergy Allergy An abnormal adaptive immune response that may or may not involve antigen-specific IgE Type I Hypersensitivity Reaction to sulfa drugs
    • Gout Gout Gout is a heterogeneous metabolic disease associated with elevated serum uric acid levels (> 6.8 mg/dL) and abnormal deposits of monosodium urate in tissues. The condition is often familial and is initially characterized by painful, recurring, and usually monoarticular acute arthritis, or “gout flare,” followed later by chronic deforming arthritis. Gout
  • Thiazide Thiazide Heterocyclic compounds with sulfur and nitrogen in the ring. This term commonly refers to the benzothiadiazines that inhibit sodium-potassium-chloride symporters and are used as diuretics. Hyponatremia precautions:
    • Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
    • Hypercalcemia Hypercalcemia Hypercalcemia (serum calcium > 10.5 mg/dL) can result from various conditions, the majority of which are due to hyperparathyroidism and malignancy. Other causes include disorders leading to vitamin D elevation, granulomatous diseases, and the use of certain pharmacological agents. Symptoms vary depending on calcium levels and the onset of hypercalcemia. Hypercalcemia
    • Hepatic impairment
    • Certain medications:
    • Pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care and lactation Lactation The processes of milk secretion by the maternal mammary glands after parturition. The proliferation of the mammary glandular tissue, milk synthesis, and milk expulsion or let down are regulated by the interactions of several hormones including estradiol; progesterone; prolactin; and oxytocin. Breastfeeding

Comparison of Medications

Some of the other most common diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication include loop diuretics Loop diuretics Loop diuretics are a group of diuretic medications primarily used to treat fluid overload in edematous conditions such as heart failure and cirrhosis. Loop diuretics also treat hypertension, but not as a 1st-line agent. Loop Diuretics (e.g., furosemide Furosemide A benzoic-sulfonamide-furan. It is a diuretic with fast onset and short duration that is used for edema and chronic renal insufficiency. Loop Diuretics), potassium-sparing diuretics Potassium-sparing diuretics Potassium-sparing diuretics are medications that act in the principal cells in the collecting ducts to induce diuresis that does not result in excretion of potassium. These diuretics include 2 subclasses: sodium channel blockers and aldosterone antagonists. Potassium-sparing Diuretics (e.g., spironolactone Spironolactone A potassium sparing diuretic that acts by antagonism of aldosterone in the distal renal tubules. It is used mainly in the treatment of refractory edema in patients with congestive heart failure, nephrotic syndrome, or hepatic cirrhosis. Its effects on the endocrine system are utilized in the treatments of hirsutism and acne but they can lead to adverse effects. Potassium-sparing Diuretics), carbonic anhydrase inhibitors Carbonic anhydrase inhibitors Carbonic anhydrase inhibitors (CAIs) block the carbonic anhydrase enzymes in the proximal convoluted tubule, inhibiting the reabsorption of sodium bicarbonate (NaHCO3), which results in diuresis and metabolic acidosis. Carbonic Anhydrase Inhibitors (e.g., acetazolamide Acetazolamide One of the carbonic anhydrase inhibitors that is sometimes effective against absence seizures. It is sometimes useful also as an adjunct in the treatment of tonic-clonic, myoclonic, and atonic seizures, particularly in women whose seizures occur or are exacerbated at specific times in the menstrual cycle. However, its usefulness is transient often because of rapid development of tolerance. Its antiepileptic effect may be due to its inhibitory effect on brain carbonic anhydrase, which leads to an increased transneuronal chloride gradient, increased chloride current, and increased inhibition. Carbonic Anhydrase Inhibitors), and osmotic diuretics Osmotic diuretics Osmotic diuretics increase tubular fluid osmolarity, pulling water into the collecting tubules and preventing water reabsorption, which results in osmotic diuresis. The primary osmotic diuretic used clinically is mannitol. The primary indication for mannitol is to treat cases of increased intracranial or intraocular pressure. Osmotic Diuretics (e.g., mannitol Mannitol A diuretic and renal diagnostic aid related to sorbitol. It has little significant energy value as it is largely eliminated from the body before any metabolism can take place. It can be used to treat oliguria associated with kidney failure or other manifestations of inadequate renal function and has been used for determination of glomerular filtration rate. Mannitol is also commonly used as a research tool in cell biological studies, usually to control osmolarity. Osmotic Diuretics).

Table: Comparison of diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication
Medication Mechanism Physiologic effect Indication
Thiazide Thiazide Heterocyclic compounds with sulfur and nitrogen in the ring. This term commonly refers to the benzothiadiazines that inhibit sodium-potassium-chloride symporters and are used as diuretics. Hyponatremia diuretic: Hydrochlorothiazide ↓ Reabsorption of NaCl in the DCT through the inhibition of Na+/Cl cotransporter
  • ↓ Blood pressure
  • Edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema
  • Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
  • Edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema
Loop diuretic: Furosemide Furosemide A benzoic-sulfonamide-furan. It is a diuretic with fast onset and short duration that is used for edema and chronic renal insufficiency. Loop Diuretics Inhibits the luminal Na+/K+/Cl cotransporter in the thick ascending limb Thick ascending limb Renal Sodium and Water Regulation of the loop of Henle Loop of Henle The U-shaped portion of the renal tubule in the kidney medulla, consisting of a descending limb and an ascending limb. It is situated between the proximal kidney tubule and the distal kidney tubule. Tubular System
  • Edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema
  • ↓ Blood pressure
  • Edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema/ ascites Ascites Ascites is the pathologic accumulation of fluid within the peritoneal cavity that occurs due to an osmotic and/or hydrostatic pressure imbalance secondary to portal hypertension (cirrhosis, heart failure) or non-portal hypertension (hypoalbuminemia, malignancy, infection). Ascites
  • CHF CHF Congestive heart failure refers to the inability of the heart to supply the body with normal cardiac output to meet metabolic needs. Echocardiography can confirm the diagnosis and give information about the ejection fraction. Congestive Heart Failure
  • Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
Potassium-sparing diuretic: Spironolactone Spironolactone A potassium sparing diuretic that acts by antagonism of aldosterone in the distal renal tubules. It is used mainly in the treatment of refractory edema in patients with congestive heart failure, nephrotic syndrome, or hepatic cirrhosis. Its effects on the endocrine system are utilized in the treatments of hirsutism and acne but they can lead to adverse effects. Potassium-sparing Diuretics
  • ↓ Reabsorption of Na through the ENaC ENaC Sodium channels found on salt-reabsorbing epithelial cells that line the distal nephron; the distal colon; salivary ducts; sweat glands; and the lung. They are amiloride-sensitive and play a critical role in the control of sodium balance, blood volume, and blood pressure. Liddle Syndrome channels Channels The Cell: Cell Membrane in the CD
  • Inhibition of aldosterone Aldosterone A hormone secreted by the adrenal cortex that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium. Hyperkalemia receptors Receptors Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors in the CD
  • ↓ Blood pressure
  • Edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema
  • Does not cause ↑ excretion of K+
  • Anti-androgenic effects
  • CHF CHF Congestive heart failure refers to the inability of the heart to supply the body with normal cardiac output to meet metabolic needs. Echocardiography can confirm the diagnosis and give information about the ejection fraction. Congestive Heart Failure
  • Edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema/ ascites Ascites Ascites is the pathologic accumulation of fluid within the peritoneal cavity that occurs due to an osmotic and/or hydrostatic pressure imbalance secondary to portal hypertension (cirrhosis, heart failure) or non-portal hypertension (hypoalbuminemia, malignancy, infection). Ascites
  • Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
  • Hirsutism Hirsutism A condition observed in women and children when there is excess coarse body hair of an adult male distribution pattern, such as facial and chest areas. It is the result of elevated androgens from the ovaries, the adrenal glands, or exogenous sources. The concept does not include hypertrichosis, which is an androgen-independent excessive hair growth. Polycystic Ovarian Syndrome in females
  • Primary hyperaldosteronism Primary hyperaldosteronism Autonomous (renin-independent) secretion of aldosterone. Hyperaldosteronism
Carbonic anhydrase inhibitor Carbonic Anhydrase Inhibitor Glaucoma: Acetazolamide Acetazolamide One of the carbonic anhydrase inhibitors that is sometimes effective against absence seizures. It is sometimes useful also as an adjunct in the treatment of tonic-clonic, myoclonic, and atonic seizures, particularly in women whose seizures occur or are exacerbated at specific times in the menstrual cycle. However, its usefulness is transient often because of rapid development of tolerance. Its antiepileptic effect may be due to its inhibitory effect on brain carbonic anhydrase, which leads to an increased transneuronal chloride gradient, increased chloride current, and increased inhibition. Carbonic Anhydrase Inhibitors Inhibits both the hydration of CO2 in the PCT PCT The renal tubule portion that extends from the bowman capsule in the kidney cortex into the kidney medulla. The proximal tubule consists of a convoluted proximal segment in the cortex, and a distal straight segment descending into the medulla where it forms the u-shaped loop of henle. Osmotic Diuretics epithelial cells and the dehydration Dehydration The condition that results from excessive loss of water from a living organism. Volume Depletion and Dehydration of H2CO3 in the PCT PCT The renal tubule portion that extends from the bowman capsule in the kidney cortex into the kidney medulla. The proximal tubule consists of a convoluted proximal segment in the cortex, and a distal straight segment descending into the medulla where it forms the u-shaped loop of henle. Osmotic Diuretics lumen; results in ↑ HCO3 and Na+ excretion
  • ↑ Urinary excretion of HCO3 → metabolic acidosis Acidosis A pathologic condition of acid accumulation or depletion of base in the body. The two main types are respiratory acidosis and metabolic acidosis, due to metabolic acid build up. Respiratory Acidosis
  • Intraocular pressure Intraocular Pressure The pressure of the fluids in the eye. Ophthalmic Exam
  • Edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with metabolic alkalosis Alkalosis A pathological condition that removes acid or adds base to the body fluids. Respiratory Alkalosis
  • Altitude sickness Altitude Sickness Altitude sickness refers to a spectrum of symptoms caused by physiological changes in the human body at altitudes above 2,500 m. Altitude sickness includes acute mountain sickness (AMS), high-altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE). Altitude Sickness
  • Intraocular pressure Intraocular Pressure The pressure of the fluids in the eye. Ophthalmic Exam
  • Off label: normal pressure hydrocephalus Normal Pressure Hydrocephalus Normal pressure hydrocephalus (NPH) is a neurodegenerative disorder characterized by the triad of gait abnormalities, dementia, and urinary urgency or incontinence. Normal pressure hydrocephalus can be either idiopathic or secondary to intraventricular or subarachnoid hemorrhage. Normal Pressure Hydrocephalus
Osmotic diuretics Osmotic diuretics Osmotic diuretics increase tubular fluid osmolarity, pulling water into the collecting tubules and preventing water reabsorption, which results in osmotic diuresis. The primary osmotic diuretic used clinically is mannitol. The primary indication for mannitol is to treat cases of increased intracranial or intraocular pressure. Osmotic Diuretics: Mannitol Mannitol A diuretic and renal diagnostic aid related to sorbitol. It has little significant energy value as it is largely eliminated from the body before any metabolism can take place. It can be used to treat oliguria associated with kidney failure or other manifestations of inadequate renal function and has been used for determination of glomerular filtration rate. Mannitol is also commonly used as a research tool in cell biological studies, usually to control osmolarity. Osmotic Diuretics Osmotic pressure Osmotic pressure The pressure required to prevent the passage of solvent through a semipermeable membrane that separates a pure solvent from a solution of the solvent and solute or that separates different concentrations of a solution. It is proportional to the osmolality of the solution. Intravenous Fluids in the glomerular filtrate → ↑ tubular fluid and prevents water reabsorption
  • ↓ Free water
  • ↓ Cerebral blood volume
  • Increased intracranial pressure Increased Intracranial Pressure Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP)
  • Increased intraocular pressure Intraocular Pressure The pressure of the fluids in the eye. Ophthalmic Exam
PCT PCT The renal tubule portion that extends from the bowman capsule in the kidney cortex into the kidney medulla. The proximal tubule consists of a convoluted proximal segment in the cortex, and a distal straight segment descending into the medulla where it forms the u-shaped loop of henle. Osmotic Diuretics: proximal convoluted tubule Proximal convoluted tubule The renal tubule portion that extends from the bowman capsule in the kidney cortex into the kidney medulla. The proximal tubule consists of a convoluted proximal segment in the cortex, and a distal straight segment descending into the medulla where it forms the u-shaped loop of henle. Osmotic Diuretics
DCT: distal convoluted tubule Distal convoluted tubule The portion of renal tubule that begins from the enlarged segment of the ascending limb of the loop of henle. It reenters the kidney cortex and forms the convoluted segments of the distal tubule. Gitelman Syndrome
CHF CHF Congestive heart failure refers to the inability of the heart to supply the body with normal cardiac output to meet metabolic needs. Echocardiography can confirm the diagnosis and give information about the ejection fraction. Congestive Heart Failure: congestive heart failure Congestive heart failure Congestive heart failure refers to the inability of the heart to supply the body with normal cardiac output to meet metabolic needs. Echocardiography can confirm the diagnosis and give information about the ejection fraction. Congestive Heart Failure
Diuretics

The sites of action within the nephron Nephron The functional units of the kidney, consisting of the glomerulus and the attached tubule. Kidneys: Anatomy for the diuretic drug classes

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References

  1. Akbari P, Khorasani-Zadeh A. (2020). StatPearls. https://www.ncbi.nlm.nih.gov/pubmed/30422513
  2. Heymann WR. (2019). The expanding saga of hydrochlorothiazide and skin cancer. J Am Acad Dermatol https://www.ncbi.nlm.nih.gov/pubmed/30529707
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  4. Roush GC, Abdelfattah R, Song S, Ernst ME, Sica DA, Kostis JB. (2018). Hydrochlorothiazide vs chlorthalidone, indapamide, and potassium-sparing/hydrochlorothiazide diuretics for reducing left ventricular hypertrophy: a systematic review and meta-analysis. J Clin Hypertens (Greenwich). https://www.ncbi.nlm.nih.gov/pubmed/30251403
  5. Musini VM, Nazer M, Bassett K, Wright JM. (2014). Blood pressure-lowering efficacy of monotherapy with thiazide diuretics for primary hypertension. Cochrane Database Syst Rev. https://www.ncbi.nlm.nih.gov/pubmed/22526259
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  10.  Lexicomp Drug Topic Pages: Hydrochlorothiazide; Chlorothiazide; chlorthalidone; indapamide; metolazone. Retrieved June 14, 2021, from https://www.uptodate.com/contents/hydrochlorothiazide-drug-information
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