Using alcohol or tobacco with certain medicines may also cause interactions to occur. This medication is taken with or without food an hour before sex. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail. You are encouraged to report adverse events related to Viatris products by calling U. Work through relationship issues. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide.Drug Images What is Viagra? If you have erectile dysfunction (ED), your doctor may recommend that you take Viagra. It’s a prescription drug that’s used in adult . Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes . VIAGRA can cause your blood pressure to drop suddenly to an unsafe level if taken with certain other medicines. Do not take VIAGRA if you take any other medicines called .