Most accurate treatment for erectile dysfunction is

Sildenafil citrate has been used for the treatment of erectile dysfunction. Rapidly absorbed after oral administration, the maximum plasma concentration is reached in 30-120 minutes. It is metabolised in liver (mainly by cytochrome P450 3A4) and is conveed to an active metabolite. Sildenafil has a terminal half-life of about 4 hours. It is highly bound to plasma proteins and is not dialyzable. It is a competitive and selective inhibitor of cGMP (cyclic guanosine monophosphate)-specific PDE-5 (phosphodiesterase type 5). It prevents the rate of breakdown of cGMP causing enhanced relaxation of cavernosal smooth muscle, increase in aerial flow into corpus cavernosa, compression of subtunical veins, and hence penile erection. The typical dose is 50 mg (25-100 mg), 1 hour before sexual activity. The maximum recommended dosing frequency is once a day. The adverse effects include a transient and mild headache, flushing, dyspepsia, and nasal congestion. Caution needs to be exercised in patients with known history of hypersensitivity, Other similar drugs include tadalafil and vardenafil. Ref: A Sho Textbook of Psychiatry, Niraj Ahuja, 7th Edition, pg. no. 132