Common ones include: Flushing of the skin. These include itraconazole Sporanox, Tolsura , ketoconazole Extina, Ketozole, others and ritonavir Norvir. Often, these are prescribed for chest pain called angina. These medicines all work well for ED. It might work longer if you have mild to moderate erectile dysfunction. Oral ED medicines might not work or might be dangerous if you also take any of the following: Nitrate medicines. These medicines are called PDE5 inhibitors.Compare prices and print coupons for Viagra (Sildenafil) and other drugs at CVS, Walgreens, and other pharmacies. Prices start at $ · You’ll typically take Viagra about 1 hour before sex. You can take the drug 30 minutes to 4 hours before you anticipate sexual activity. Based on how well you respond to this dosage and any side. Get drug information. Search for a drug by name or NDC number and get complete drug information. It’s like the printout attached to your refill—only electronic. Help me find my info. Search by name. Search by NDC. Enter medication name (Ex. “Lipitor”).