RELATED TOPIC:
Nursing Knowledge
Pharmacokinetics is the study of how a drug moves through the body, including processes of absorption, distribution, metabolism, and excretion.
Learning about this is essential for nurses as it helps determine the dosage, administration route, and frequency of medication, considering factors like the client’s age, weight, disease state, and liver and kidney functions, to ensure optimal therapeutic effect and minimize adverse effects.
The absorption rate determines how fast and how much of the drug reaches the bloodstream and can take effect. It's affected by factors such as administration route, metabolic rate, and food interactions.
Bioavailability is the percentage of the administered drug that reaches the systemic circulation intact (extent and rate at which the drug enters the systemic circulation). It impacts drug efficacy and dosing decisions.
Bioavailability is 100% in IV administration, but varies widely in all other routes.
Metabolism, mainly in the liver, transforms the drug into a form that can be excreted. Some drugs are activated or deactivated during this phase, influencing drug effect.
Factors that influence where the drug will take effect include:
The cytochrome P450 system is a group of 12 closely related enzyme families responsible for metabolism of most drugs.
Genetic variability in CYP450 enzyme function contributes to differences in individuals’ ability to metabolize drugs. Many foods and medications can inhibit or induce the CYP450 enzyme system. It is important to counsel clients regarding the potential food and drug interactions of their specific medications.
The "first pass effect" refers to the fact that drugs that are administered orally and absorbed from the gastrointestinal tract are first transported to the liver and metabolized there, before entering the systemic circulation.
This can significantly decrease bioavailability and therefore must be considered when determining the appropriate dosage for oral medications.
RELATED TOPIC:
Free Download
Master the topic with a unique study combination of a concise summary paired with video lectures.
USMLE™ is a joint program of the Federation of State Medical Boards (FSMB®) and National Board of Medical Examiners (NBME®). MCAT is a registered trademark of the Association of American Medical Colleges (AAMC). NCLEX®, NCLEX-RN®, and NCLEX-PN® are registered trademarks of the National Council of State Boards of Nursing, Inc (NCSBN®). None of the trademark holders are endorsed by nor affiliated with Lecturio.
Your free account gives you access to:
or
