They have the same benefits and risks as their brand-name counterparts. People taking nitrates like nitroglycerin Nitrostat or isosorbide mononitrate Imdur should not take PDE5 inhibitors, as doing so could result in a dangerous drop in blood pressure. Insurance can help you save even more on consultations and medications. How safe is Viagra? Levitra vardenafil : This medication is taken one hour before sex and can last up to 24 hours. The specific process for getting ED pills online depends on your chosen provider. While each PDE5 inhibitor differs slightly, they’re very similar in treating erectile dysfunction.The key difference is the price: Viagra costs more than Sildenafil because it’s a brand-name medication. We carry both versions, Sildenafil and Viagra, so you can choose the Viagra . Typical dosing for Sildenafil (Viagra) The typical dose is to take 50 mg of sildenafil (Viagra) by mouth, about 1 hour before sex, as needed. The maximum recommended dose is . Generic Viagra (sildenafil): $4 per 25 mg pill, $6 per 50 mg pill, $10 per mg pill; Branded.