RELATED TOPIC:
Nursing Knowledge
Erectile dysfunction (ED) is the inability to achieve or maintain an erection sufficient for sexual intercourse.
Risk factors for ED include:
Clinical tip: Erectile dysfunction can be an early warning sign of a wide range of serious conditions, including cardiovascular disease and diabetes. Clients who report erectile dysfunction should be screened for underlying pathology.
Erectile dysfunction is treatable with phosphodiesterase inhibitors:
All of those medications are administered orally and are typically taken 15–60 minutes before sexual activity. Tadalafil can be taken daily.
Cyclic GMP (cGMP) is an enzyme that regulates ion channel conduction in smooth muscle, causing vasodilation. Phosphodiesterase 5 (PDE5) is an enzyme that breaks down cGMP, leading to vasoconstriction.
PDE5 inhibitors block PDE5 function, which prevents the breakdown of cGMP. Higher cGMP levels increase vasodilation. Increased vasodilation facilitates penile engorgement and sustained erectile function.
Common side effects occurring with ED drugs include:
Precautions:
Table: Comparison of erectile dysfunction drugs
| Sildenafil (Viagra) | Tadalafil (Cialis) | Vardenafil (Levitra) | Avanafil (Stendra) | |
| Onset | 30–60 minutes | 30–45 minutes (sometimes sooner) | 30–60 minutes | Quickest; 15–30 minutes |
| Duration of action | 4–6 hours | Up to 36 hours | 4–6 hours | 6–12 hours |
| Food interactions | High-fat meal can slow absorption. | Not significantly impacted | High-fat meal can slow absorption. | Not significantly impacted |
A notable difference between the well-known drugs sildenafil (Viagra) and tadalafil (Cialis) is the duration of action: While sildenafil works for about 4–6 hours, tadalafil can have an effect for up to 36 hours, allowing for more spontaneity and earning the medication the nickname “weekend pill.”
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
