A newer form of the medicine that dissolves on the tongue might work faster than the pill that you swallow. There are many factors to considering when shopping for health insurance including rate, coverage, HMO vs. Find out whether Viagra is covered under the prescription coverage component of your insurance plan. Medicines that you take by mouth are called oral medicines. The four main medicines taken by mouth for erectile dysfunction are: Avanafil Stendra. Some examples of nitrates are nitroglycerin Nitro-Dur, Nitrostat, others , isosorbide mononitrate Monoket and isosorbide dinitrate Bidil. Severe liver disease.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 . After discussing your erectile dysfunction and your medical history, ask your doctor for a prescription for Viagra. You may have your doctor’s office directly submit the script to . You can ask for recommendations from: your PCP other healthcare providers trusted friends or family members You should also check a doctor’s credentials on your state medical .