Tadalafil relaxes muscles and increases blood flow to particular areas of the body.

Tadalafil under the name of Cialis is used to treat erectile dysfunction (impotence) and symptoms of benign prostatic hypertrophy (enlarged prostate). Another brand of tadalafil is Adcirca, which is used to treat pulmonary arterial hypertension and improve exercise capacity in men and women.

Tadalafil may also be used for purposes not listed in this medication guide.

Do not take tadalafil if you are allergic to it, or if you are also using a nitrate drug for chest pain or heart problems, including nitroglycerin (Nitro Dur, Nitrolingual, Nitrostat, Transderm Nitro, and others), isosorbide dinitrate (Dilatrate, Isordil, Isochron), isosorbide mononitrate (Imdur, ISMO, Monoket), or recreational drugs such as amyl nitrate or nitrite ("poppers"). Taking tadalafil with a nitrate medicine can cause a sudden and serious decrease in blood pressure.

If you become dizzy or nauseated during sexual activity, or if you have pain, numbness, or tingling in your chest, arms, neck, or jaw, stop and call your doctor right away. You could be having a serious side effect of tadalafil.

Do not take tadalafil more than once a day. Allow 24 hours to pass between doses.

Contact your doctor or seek emergency medical attention if your erection is painful or lasts longer than 4 hours. A prolonged erection (priapism) can damage the penis.

Tadalafil can decrease blood flow to the optic nerve of the eye, causing sudden vision loss. This has occurred in a small number of people taking tadalafil, most of whom also had 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. It is not clear whether tadalafil is the actual cause of vision loss.

Stop using tadalafil and get emergency medical help if you have sudden vision loss.

You should not take tadalafil if you are allergic to it.

Tadalafil should not be used together with nitrate medication, such as nitroglycerin (Nitro Dur, Nitrolingual, Nitrostat, Transderm Nitro, and others), isosorbide dinitrate (Dilatrate, Isordil, Isochron), isosorbide mononitrate (Imdur, ISMO, Monoket), or recreational drugs such as amyl nitrate or nitrite ("poppers"). Taking tadalafil with a nitrate medicine for chest pain or heart problems can cause a sudden and serious decrease in blood pressure.

To make sure you can safely take tadalafil, tell your doctor if you have any of these other conditions:

• heart disease or heart rhythm problems;

• a recent heart attack (within the past 90 days);

• a recent history (in the past 6 months) of a stroke, or congestive heart failure;

• angina (chest pain), high or low blood pressure;

• liver disease;

• kidney disease (or if you are on dialysis);

• 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.

Tadalafil can decrease blood flow to the optic nerve of the eye, causing sudden vision loss. This has occurred in a small number of people taking tadalafil, most of whom also had 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.

It is not clear whether tadalafil is the actual cause of vision loss. Stop using tadalafil and get emergency medical help if you have sudden vision loss.

FDA pregnancy category B. Tadalafil is not expected to harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment with Adcirca.

It is not known whether tadalafil passes into breast milk or if it could harm a nursing baby. Do not use Adcirca without telling your doctor if you are breast-feeding a baby.