Some services offer a subscription option where they’ll send your medications every month at a discount. Most erectile dysfunction medications belong to the drug class known as PDE5 inhibitors , which help relax the muscles and increase blood flow to allow for a full erection. Alpha-blockers are sometimes prescribed for prostate problems or high blood pressure. These PDE5 inhibitors may cause headache, flushing, drop in blood pressure, or other adverse effects. 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. It’s available in 10 mg and 20 mg tablets. You should also call your insurance company to see if they cover erectile dysfunction medications.According to price-comparison site , generic Revatio will cost you as little as $ per pill, depending on where you fill your prescription. That’s compared with . Compare prices and print coupons for Sildenafil (Generic Revatio and Viagra) and other drugs at CVS, Walgreens, and other pharmacies. Prices start at $ Generic name: sildenafil (oral) [ sil-DEN-a-fil ] Brand names: Revatio, Viagra Drug class: Impotence agents Medically reviewed by Sophia Entringer, PharmD. Last updated on .