Viagra is used to treat impotence in men. Viagra increases the body’s ability to achieve and maintain an erection during sexual stimulation. Viagra does not protect you from getting sexually transmitted diseases, including HIV. Viagra comes as a tablet to take it orally. It should be taken as needed about 1 hour before sexual activity. However, Viagra can be taken anytime from 4 hours to 30 minutes before sexual activity. Viagra should not be taken more than once a day. Do not take more or less of it or take it more often than prescribed by your doctor.
- nitroglycerin (inhalers, ointments, dermal patches or pastes, or tablets for ingestion, chewing or resorption in the oral cavity);
- isosorbide mononitrate or isosorbide dinitrate (tablets for ingestion, chewing or resorption in the oral cavity).