Sildenafil — Phosphodiesterase type 5 (PDE5) inhibitor

Sildenafil should be taken on an empty stomach for fastest absorption; high-fat meals delay peak concentration by ~60 minutes. The 'blue vision' effect (cyanopsia) is due to weak inhibition of PDE6 in the retina. Tadalafil (Cialis) has a much longer half-life (17.5h) allowing for 'once-daily' dosing and less time-dependence on activity. Safety with alpha-blockers: both can cause hypotension — doses should be separated and patient stabilized on alpha-blocker first. Sildenafil is being investigated for cognitive benefits/dementia prevention via cerebral blood flow enhancement, but clinical evidence is currently insufficient to recommend use.

نظرة عامة

هذه الصفحة جزء من مكتبة المركّبات المُصنَّفة بالأدلة في Hormonaly. جميع الادعاءات السريرية مرتبطة بمصادر علمية مُحكَّمة عبر خط أنابيب التحقق المزدوج للاستشهادات.

فئة المركّب

Phosphodiesterase type 5 (PDE5) inhibitor

آلية العمل

Potent and selective inhibitor of cGMP-specific phosphodiesterase type 5 (PDE5). In the corpus cavernosum, nitric oxide (NO) stimulates cGMP production, which causes smooth muscle relaxation and inflow of blood. Sildenafil prevents the degradation of cGMP by PDE5, thus enhancing the vasodilatory effect of NO. Important: Sildenafil has no effect in the absence of sexual stimulation. In pulmonary hypertension (Revatio), it increases cGMP in pulmonary vascular smooth muscle cells resulting in vasodilation of the pulmonary arterial bed. Half-life ~4 hours. Onset 30-60 minutes.

الوضع التنظيمي

FDA approved — Viagra 1998, Revatio 2005

مستوى الأدلة

High — FDA-approved 1998 (Viagra), 2005 (Revatio); extensive RCT data