Why is Viagra prescribed?

Viagra is used to treat impotence in men. Viagra increases the body's ability to achieve and maintain an erection during sexual stimulation.

Sildenafil citrate is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

How should Viagra be used?

Viagra comes as a tablet to take by mouth. 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. Sildenafil citrate should not be taken more than once a day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take Sildenafil citrate exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

What special precautions should I follow?

Before taking Viagra,

• tell your doctor and pharmacist if you are allergic to Viagra or any other drugs.
• tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially amlodipine (Norvasc) or other medications for high blood pressure, cimetidine (Tagamet, Tagamet HB), erythromycin, HIV protease inhibitors such as ritonavir (Norvir) and saquinavir (Invirase), isosorbide (Imdur, Ismo, Isordil, and others), itraconazole (Sporanox), ketoconazole (Nizoral), nitroglycerin (Nitro-Bid, Nitrostat, and others), other medications to treat impotence, phenobarbital, rifampin (Rifadin, Rimactane),and vitamins.
• tell your doctor if you have or have ever had a bleeding disorder; heart, kidney, or liver disease; a heart attack; irregular heartbeats; angina; a stroke; high or low blood pressure; sickle cell anemia; multiple myeloma; leukemia; conditions affecting the shape of the penis (e.g., angulation, cavernosal fibrosa, or Peyronie's disease); or a condition known as retinitis pigmentosa.
• if you are having surgery, including dental surgery, tell your doctor or dentist that you take Sildenafil citrate.
• tell your doctor if you use amyl nitrate, amyl nitrite, or butyl nitrate.

What side effects can Viagra cause?

Although side effects from Sildenafil citrate are not common, they can occur. Tell your doctor if any of these symptoms are severe or do not go away:

• headache
• upset stomach
• diarrhea
• dizziness or lightheadedness
• flushing (feeling of warmth)
• nasal congestion (stuffiness)
• changes in vision
• breast enlargement

If you experience any of the following symptoms, call your doctor immediately:

• rash
• painful erection
• prolonged erection (longer than 4 hours)
• fainting
• chest pain
• itching or burning during urination

What storage conditions are needed for Viagra?

Keep Sildenafil citrate in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

What other information should I know?

Keep all appointments with your doctor. Viagra is not effective in preventing the spread of AIDS or other sexually transmitted diseases. Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.