EMMANUELEMMANUEL MICHAEL

1.INTRODUCTION

Sildenafil citrate sold as Viagra,Revatio and under various other trade nameIs a drug used to treat erectile dysfuction and pulmonary arterial hypertension.

STRUCTURE

Mechanism of Action

It acts by inhibiting Cgmp specific phosphodiasterase type 5 PDE5 an enzyme that promotes degradation of c GMP which regulate blood in the penis.

OTHER DRUGS WITH SIMILAR MECHANISM OF ACTION

•Tadalafil-Cialis•Vardenafil-Levitra

INDICATION•The primary indication of sildenafil is treatment of erectile dysfuction(inability to sustain satisfactory erection to complete intercourse)•Its use is now standard treatment for erectile dysfuction in all setting

Indication continued……………………•As well as erectile dysfuction sildenafil citrate is also effective in Pulmonary Arterial Hypertension(PAH)•It relaxes the arterial wall,leading to decreased pulmonary arterial resistance and pressure.

DOSAGE

Viagra pills are available in 25mg,50mg and 100mg from

ADVERSE EFFECTS•Dyspepsia•Nausea•Headache•Visual disturbance•Back pain•Dizziness•Less common are tinnitus,dry mouth,drowsiness,vertigo and fatigue

INTERACTION

• Protease inhibitors for treatment of HIV• Its recommended that patients using

protease inhibitor limit their use of sildenafil to more than one 25mg every 48 hours

• Alpha blockers-concomitant use lead to low blood pressure.

CONTRAINDICATION

•When taking nitric oxide donors,organic nitrites,and nitrates such as nitroglycerin,sodium nitroprusside and amy nitrite•Severe hepatic impairment•Severe impairment in renal function•Cardiovascular problem•Recent stroke or heart attack