ED medications can cause side effects, and it’s crucial to have access to a medical provider if needed. There are no antidotes available for sildenafil. Payment options: Consider how you’d like to pay. The onset of action can occur within 30 minutes, while the duration of the effect can last up to 18 hours. Both options require valid medical documentation, but some online services only require a health questionnaire to be filled out and reviewed for approval—meaning no face-to-face video interaction is needed. Contraindications Nitrates increase cGMP formation, while sildenafil inhibits cGMP degradation causing the combination to produce severe life-threatening hypotension synergistically; coadministration of sildenafil with nitrates is contraindicated. The recommended dosage for tablet and oral suspension formularies is 5 mg or 20 mg three times daily, 4 to 6 hours apart.Real Doctors · Free Shipping · Discreet Packaging · Personalized Plan/5 (3, reviews)Site visitors: Over 10K in the past month. VigRx Plus – Buy 3 Get 2 Free! Adult 60 Count (Pack of 5) out of 5 stars 2. $ $ 85 ($/Count) FREE delivery Fri, Nov Shop products from small business . Sildenafil (Viagra) is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. Sildenafil (Liqrev, Revatio) is used to improve the ability to exercise in adults (Liqrev, Revatio) and children 1 year of age and older (Revatio) with pulmonary arterial hypertension (PAH; high blood pressure in the vessels carrying blood to the .