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

Tadalafil is used to treat erectile dysfunction (impotence).

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

* Taking tadalafil with any of these medications may cause very low blood pressure, possibly resulting in dizziness, fainting, stroke, or heart attack.

* Contact your doctor or seek emergency medical attention for any erection that lasts longer than 4 hours. A sustained erection can damage the penis.

* Refrain from further sexual activity and notify your doctor it you develop dizziness, nausea, or angina (pain, tightness, discomfort, numbness, or tingling in the chest, arms, neck, or jaw) during sexual activity.

* Tadalafil is usually taken when needed before sexual activity. The effects of tadalafil may last for up to 36 hours or more. Your doctor will determine how often you can take tadalafil. Do not take tadalafil more often than is directed by your doctor.

Special precautions

Before taking tadalafil, tell your doctor if you

• have heart problems such as angina, heart failure, irregular heartbeats, or have had a heart attack;

• have low blood pressure or high blood pressure that is not controlled;

• have had a stroke;

• have liver problems;

• have kidney problems;

• have ever had blood cell problems such as sickle cell anemia, multiple myeloma, or leukemia;

• have a bleeding disorder;

• have a stomach ulcer;

• have retinitis pigmentosa (an inherited condition of the eye);

• have a physical deformity of the penis such as Peyronie's disease;

• Had an erection that lasted longer than 4 hours.

* Taking tadalafil with any of these medications may cause very low blood pressure, possibly resulting in dizziness, fainting, stroke, or heart attack.

* You may not be able to take tadalafil, or you may require a dosage adjustment or special monitoring during treatment if you have any of the conditions listed above.

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

* It is not known whether tadalafil passes into breast milk. Tadalafil should not be taken by women.

* If you are over 65 years of age, you may be more likely to experience side effects from tadalafil. Your doctor may prescribe a lower dose of this medication.

Side effects

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

• an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives);

• chest pain or irregular heartbeats;

• dizziness, nausea, or angina (pain, tightness, discomfort, numbness, or tingling in the chest, arms, neck, or jaw);

• swelling of the ankles or legs;

• shortness of breath;

• prolonged or severe dizziness; or

• A prolonged (lasting longer than 4 hours) or painful erection.

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

• headache;

• indigestion;

• back pain;

• muscle aches;

• flushing;

• stuffy or runny nose; or

• Temporary blue tint in vision or difficulty telling the difference between the colors blue and green (uncommon).

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.