They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide. Most online providers require a picture of a valid ID, a selfie showing your face, and a recent blood pressure reading taken with a home blood pressure monitor or by a medical provider. Some men get side effects from using Viagra, but most of the time these are mild and disappear after a couple of uses. However, some states require a live video consultation. Next review due on August 01, In some patients, the use of VIAGRA with alpha-blockers can lead to a drop in blood pressure or to fainting medicines called HIV protease inhibitors, such as ritonavir Norvir , indinavir sulfate Crixivan , saquinavir Fortovase or Invirase , or atazanavir sulfate Reyataz some types of oral antifungal medicines, such as ketoconazole Nizoral and itraconazole Sporanox some types of antibiotics, such as clarithromycin Biaxin , telithromycin Ketek , or erythromycin other medicines that treat high blood pressure other medicines or treatments for ED VIAGRA contains sildenafil, which is the same medicine found in another drug called REVATIO.Check Your Pills Check your pills to be sure they’re brand-name VIAGRA—not the generic. If you think your brand-name prescription has been filled with a generic, talk to your . Sildenafil (Viagra). This medicine works best when you take it on an empty stomach an hour before sex. The body takes longer to absorb it after a high-fat meal or alcohol. Its effects . Generic Viagra (sildenafil): $4 per 25 mg pill, $6 per 50 mg pill, $10 per mg pill; Branded Viagra: $90 per 25 mg, 50 mg, or mg pill; Generic Cialis (tadalafil): $11 per 5 mg .