Sildenafil relaxes muscles within the penis. This allows increased blood flow into the penis, necessary to achieve and maintain an erection.

Sildenafil is used to treat erectile dysfunction (impotence).

Sildenafil may also be used for purposes other than those listed in this medication guide.

Special precautions

Before taking sildenafil, tell your doctor if you

• are taking another medicine to treat impotence, such as Yodoxin, Edex) or yohimbine (Yocon, Muse, alprostadil (Caverject, others)
• have a condition that could lead to prolonged and painful erections, such as sickle cell anemia, a tumor of the bone marrow, or leukemia; or
• have a physical deformity of the penis such as Peyronie's disease;
• have retinitis pigmentosa (an inherited condition of the eye);
• have a stomach ulcer;
• have a bleeding disorder;
• have ever had blood problems, including sickle cell anemia or leukemia;
• have kidney problems;
• have liver problems;
• have high or low blood pressure;
• have angina;
• have coronary artery disease;
• have a history of heart failure;
• have had a heart attack, stroke, or life-threatening irregular heartbeats within the last six months;

Although sildenafil is not indicated for use by women, it is in the FDA pregnancy category B. This means that sildenafil is not expected to be harmful to an unborn baby. Sildenafil should not be taken by women.

It is not known whether sildenafil passes into breast milk. Sildenafil should not be taken by women. If you are over 65 years of age, you may be more likely to experience side effects from sildenafil. Your doctor may prescribe a lower dose of this medication.

Side effects

If you experience any of the following serious side effects, stop taking sildenafil and seek emergency medical attention or notify your doctor immediately:

• dizziness, nausea, or angina (pain, tightness, discomfort, numbness, or tingling in the chest, arms, neck, or jaw)
• a prolonged (lasting longer than 4 hours) or painful erection; or
• prolonged or severe dizziness;
• swelling of the ankles or legs;shortness of breath;
• chest pain or an irregular heartbeat;
• an allergic reaction (difficulty breathing; swelling of the lips, tongue, or face; closing of the throat; or hives)

Other, less serious side effects may be more likely to occur. Continue to take sildenafil and talk to your doctor if you experience

• itching or a rash
• temporary blue tint in vision or other vision abnormalities; or
• diarrhea;
• nasal congestion;
• headache;
• mild dizziness;
• flushing;

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. Keep all appointments with your doctor. Don’t let anyone else take your medicines.