Many people have no side effects or only mild ones. If you buy sildenafil for erectile dysfunction, it can also be known by the brand names Viagra, Aronix, Liberize and Nipatra. It can be dangerous to take sildenafil if you also take medicines called nitrates often given for chest pain. About sildenafil Viagra Sildenafil is a medicine used to treat erection problems erectile dysfunction. Do not drink grapefruit juice if you’re taking sildenafil Revatio for pulmonary hypertension.In most males,* Viagra works within 1 hour after it’s taken. It’s possible that Viagra can begin working within 30 minutes of being taken. But other times, it may take . · Viagra comes as an oral tablet that contains the active drug sildenafil. Sildenafil is also available in generic form. Viagra is classified as a phosphodiesterase type 5 (PDE5) inhibitor. The Original Male Enhancement Tablets – 30 ea. $ $ / ea$ Extra 15% off $30 Sitewid Not sold at your store. Check other stores. Shipping. New Vitality. Ageless Male Performance Tablets – 60 ea.