What is sildenafil?

• Sildenafil relaxes muscles and increases blood flow to particular areas of the body.
• Sildenafil under the name Viagra is used to treat erectile dysfunction (impotence) in men. Another brand of sildenafil is Revatio, which is used to treat pulmonary arterial hypertension and improve exercise capacity in men and women.
• Sildenafil may also be used for purposes other than those listed here.

What should I discuss with my doctor before taking sildenafil?

• Do not take sildenafil if you are also using a nitrate drug for chest pain or heart problems. This includes nitroglycerin (Nitrostat, Nitrolingual, Nitro-Dur, Nitro-Bid, and others), isosorbide dinitrate (Dilatrate-SR, Isordil, Sorbitrate), and isosorbide mononitrate (Imdur, ISMO, Monoket). Nitrates are also found in some recreational drugs such as amyl nitrate or nitrite ("poppers"). Taking sildenafil with a nitrate medicine can cause a serious decrease in blood pressure, leading to fainting, stroke, or heart attack.
• A small number of patients have had a sudden loss of eyesight after taking sildenafil. This type of vision loss is caused by decreased blood flow to the optic nerve of the eye. It is not clear whether sildenafil is the actual cause of such vision loss. Sudden vision loss with sildenafil use has occurred most often in people with heart disease, diabetes, high blood pressure, high cholesterol, or certain pre-existing eye problems, and in those who smoke or are over 50 years old.
• Before taking sildenafil, tell your doctor if you have:
  • heart disease or heart rhythm problems;
  • a recent history (in the past 6 months) of a heart attack, stroke, or heart rhythm disorder;
  • congestive heart failure;
  • high or low blood pressure;
  • coronary artery disease;
  • liver disease;
  • kidney disease;
  • a blood cell disorder such as sickle cell anemia, multiple myeloma, or leukemia;
  • a bleeding disorder such as hemophilia;
  • a stomach ulcer;
  • retinitis pigmentosa (an inherited condition of the eye);
  • a physical deformity of the penis (such as Peyronie's disease); or
  • if you have been told you should not have sexual intercourse for health reasons.
• If you have any of these conditions, you may not be able to use sildenafil or you may need a dosage adjustment or special tests during treatment.
• FDA pregnancy category B: This medication is not expected to be harmful to an unborn baby. Do not use sildenafil without telling your doctor if you are pregnant or plan to become pregnant during treatment.
• It is not known if sildenafil passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

How should I take sildenafil?

• Take each dose with a full glass of water.
• Avoid taking High-fat food before taking Viagra as it may cause the medicine to take more time to start working.
• Sildenafil is usually taken only when needed, 30 - 90 minutes before sexual activity. The medication can help achieve an erection when sexual stimulation occurs. An erection will not occur just by taking a pill.
• Do not take sildenafil more than once a day. Allow 24 hours to pass between doses.
• Store this medication at room temperature away from moisture and heat.

What happens if I miss a dose?

• Viagra is used as needed, so you are not likely to miss a dose.
• If you miss a dose of Revatio, take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the medicine at the next regularly scheduled time. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

• Seek emergency medical attention if you think you have used too much of this medicine. Symptoms of a sildenafil overdose may include chest pain, nausea, irregular heartbeat, and feeling light-headed or fainting.

What should I avoid while taking sildenafil?

• Avoid drinking alcohol, which can increase some of the side effects of sildenafil.
• Avoid using other medicines to treat impotence, such as alprostadil (Caverject, Muse, Edex) or yohimbine (Yocon, Yodoxin, others), without first talking to your doctor.

What are the possible side effects of sildenafil?

• If you become dizzy or nauseated, or have pain, numbness, or tingling in your chest, arms, neck, or jaw during sexual activity, stop and call your doctor right away. You could be having a serious side effect of sildenafil.
• Stop using sildenafil and get emergency medical help if you have sudden vision loss.
• Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
• Stop using sildenafil and call your doctor at once if you have any of these serious side effects:
  • chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, general ill feeling;
  • irregular heartbeat;
  • swelling in your hands, ankles, or feet;
  • shortness of breath;
  • vision changes;
  • feeling light-headed, fainting; or
  • penis erection that is painful or lasts 4 hours or longer.
• Continue taking sildenafil and talk with your doctor if you have any of these less serious side effects:
  • warmth or redness in your face, neck, or chest;
  • stuffy nose;
  • headache;
  • upset stomach; or
  • back pain.
• Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

What drug(s) may interact with ?

Do not take sildenafil if you are taking the following medications:

• nitroglycerin-type drugs for the heart or chest pain such as amyl nitrite, isosorbide dinitrate, isosorbide mononitrate, nitroglycerin, even if these are only taken occasionally

Sildenafil may also interact with the following medications:

• alpha blockers, used for high blood pressure or an enlarged prostate. NOTE: Do not take doses of sildenafil higher than 25 mg within 4 hours of taking alpha blockers, such as alfuzosin (UroXatral®), doxazosin (Cardura®), prazosin (Minipress®), or terazosin (Hytrin®).
• bosentan
• certain drugs used for seizures such as carbamazepine, phenytoin, and phenobarbital
• certain drugs used for fungal or yeast infections, such as fluconazole, ketoconazole, and voriconazole
• certain drugs for the treatment of HIV infection or AIDS
• cimetidine
• cisapride
• clarithromycin
• diltiazem
• erythromycin
• grapefruit juice
• mibefradil
• nitroprusside
• rifabutin
• rifampin
• quinidine
• some drugs for treating depression, anxiety or other mood problems (examples: fluoxetine, fluvoxamine, nefazodone)
• verapamil