Erectile dysfunction, or ED, is the repetitive failure to achieve or maintain a firm penile erection as desired for sexual intercourse. The American Urological Association (AUA) reports an estimated 30 million American men older than age 50 have some form of ED. Oral medications approved by the U.S. Food and Drug Administration (FDA) have become the primary form of treatment for ED.
Sildenafil
Sildenafil is an oral ED medication in the drug group known as phosphodiesterase type 5 (PDE5) inhibitors. These medications prevent the breakdown of a substance naturally produced within the penis in response to sexual stimulation. This action causes increased blood flow into the penis leading to an erection. Notably, PDE5 inhibitors affect the penis only in the presence of sexual stimulation.
Sildenafil was the first PDE5 inhibitor approved by the FDA for treatment of ED in 1998. The FDA-approved prescribing information for sildenafil indicates a typical dose is 50 mg to be taken approximately one hour before intended sexual activity. Sildenafil is also available in 25 mg and 100 mg tablets to permit dosage adjustment based on individual response, as prescribed by your doctor. Sildenafil is intended for use as needed. The AUA reports the effects of sildenafil can last from one-half hour up to four hours. Taking sildenafil with a full meal can delay the onset of drug activity.
Tadalafil
Tadalafil is a PDE5 inhibitor, which acts to improve the capacity to achieve and maintain an erection by the same mechanism as does sildenafil. The FDA approved this medication in 2003 for use on an as-needed basis. In 2009, tadalafil was approved as a once daily medication. The FDA-approved prescribing information for tadalafil indicates the usual as needed dose is 10 mg by mouth at least 30 minutes before sexual activity. The AUA notes that tadalafil absorption is not affected by food, and the effects may last for up to 36 hours. The recommended starting dose for once daily tadalafil is 2.5 mg. Tadalafil is available in 2.5, 5, 10 and 20 mg tablets. Your doctor will work with you to adjust your dose based on your response and other health-related factors.
Vardenafil
Vardenafil is a PDE5 inhibitor with a mechanism of action that mirrors other drugs in this class. The FDA approved this medication for the treatment of ED in 2003. Vardenafil is an as needed ED medication. The prescribing information indicates the starting dose is 10 mg by mouth taken approximately one hour before intended sexual activity. Other available strengths include 2.5, 5 and 20 mg tablets. Your doctor will work with you to adjust your dose if needed. Food does not affect the absorption of vardenafil. The AUA notes the effects of this medication may last from one-half hour up to four hours.
