Especially tell your healthcare provider if you take any of the following: medicines called nitrates medicines called guanylate cyclase stimulators such as Adempas riociguat medicines called alpha-blockers, such as Hytrin terazosin HCl , Flomax tamsulosin HCl , Cardura doxazosin mesylate , Minipress prazosin HCl , Uroxatral alfuzosin HCl , Jalyn dutasteride and tamsulosin HCl , or Rapaflo silodosin. Sexual activity may be a strain on your heart, especially if you have heart disease. Please expect up to 4 to 6 weeks for reimbursement. Do not take a double dose to make up for a missed one. Take sildenafil at around the same times every day. You should only be treated with one of these products at a time.If you’re holding out for a generic version of branded Viagra, you won’t have to wait much longer. Teva Pharmaceuticals plans to release its generic of the “little blue pill” as early . Viagra (sildenafil) is a prescription drug that’s used to treat erectile dysfunction (ED). The drug comes as a tablet you’ll take by swallowing. It’s usually taken as needed about 1 hour. Compare prices and print coupons for Viagra (Sildenafil) and other drugs at CVS, Walgreens, and other pharmacies. Prices start at $