Why is this medication prescribed?

Tadalafil is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. Tadalafil is in a class of medications called phosphodiesterase (PDE) inhibitors. It works by increasing blood flow to the penis during sexual stimulation. This increased blood flow can cause an erection. Tadalafil does not cure erectile dysfunction or increase sexual desire. Tadalafil does not prevent pregnancy or the spread of sexually transmitted diseases such as human immunodeficiency virus (HIV).

How should this medicine be used?

Tadalafil comes as a tablet to take by mouth. It is usually taken with or without food before sexual activity. Your doctor will help you decide the best time for you to take tadalafil before sexual activity. Tadalafil should not be taken more often than once every 24 hours. If you have certain health conditions or are taking certain medications, your doctor may tell you to take tadalafil less often. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take tadalafil exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Your doctor will probably start you on an average dose of tadalafil and increase or decrease your dose depending on your response to the medication. Tell your doctor if tadalafil is not working well or if you are experiencing side effects.

Other uses for this medicine

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What special precautions should I follow?

Before taking tadalafil,

• tell your doctor and pharmacist if you are allergic to tadalafil or any other medications.
• do not take tadalafil if you are taking alpha blockers such as alfuzosin (Uroxatral), doxazosin (Cardura), prazosin (Minipress), and terazosin (Hytrin). However, you may take tadalafil if you are taking an alpha blocker called tamsulosin (Flomax) at a dose of 0.4 mg daily. Also do not take tadalafil if you are taking or have recently taken nitrates such as isosorbide dinitrate (Isordril, Sorbitrate), isosorbide mononitrate (Imdur, ISMO), and nitroglycerin (Nitro-BID, Nitro-Dur, Nitroquick, Nitrostat, others). Nitrates come as tablets, sublingual (under the tongue) tablets, sprays, patches, pastes, and ointments. Ask your doctor if you are not sure if any of your medications contain nitrates.
• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking. Be sure to mention any of the following: antifungals such as fluconazole (Diflucan), itraconazole (Sporanox), ketoconazole (Nizoral); carbamazepine (Tegretol); cimetidine (Tagamet); clarithromycin (Biaxin); cyclosporine (Neoral, Sandimmune); danazol (Danocrine); delavirdine (Rescriptor); dexamethasone (Decadron); diltiazem (Cardizem, Dilacor, Tiazac); erythromycin (E.E.S., E-Mycin, Erythrocin); ethosuximide (Zarontin); fluoxetine (Prozac, Sarafem); fluvoxamine (Luvox); HIV protease inhibitors such as indinavir (Crixivan), nelfinavir (Viracept), and ritonavir (Norvir); isoniazid (INH, Nydrazid); medications for high blood pressure; metronidazole (Flagyl); nefazodone (Serzone);other medications or treatments for erectile dysfunction; phenobarbital (Luminal, Solfoton); phenytoin (Dilantin); rifabutin (Mycobutin); rifampin (Rifadin, Rimactane); troleandomycin (TAO), verapamil (Calan, Covera, Isoptin, Verelan), and zafirlukast (Accolate). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have or have ever had an erection that lasted more than 4 hours; a condition that affects the shape of the penis such as angulation, cavernosal fibrosis, or Peyronie's disease; high or low blood pressure; irregular heartbeat; a heart attack; angina (chest pain); a stroke; ulcers in the stomach or intestine; a bleeding disorder; blood cell problems such as sickle cell anemia (a disease of the red blood cells), multiple myeloma (cancer of the plasma cells), or leukemia (cancer of the white blood cells); and liver, kidney, or heart disease. Also tell your doctor if you or any of your family members have or have ever had an eye disease such as retinitis pigmentosa. Tell your doctor if you have ever been advised by a health care professional to avoid sexual activity for medical reasons or if you have ever experienced chest pain during sexual activity.
• you should know that tadalafil is only for use in males. Women should not take tadalafil, especially if they are or could become pregnant or are breast-feeding. If a pregnant woman takes tadalafil, she should call her doctor.
• if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking tadalafil.
• ask your doctor about the safe use of alcoholic beverages while you are taking tadalafil. Alcohol can make the side effects from tadalafil worse. Your doctor will tell you how much alcohol you may drink while you are taking this medication.
• you should know that sexual activity may be a strain on your heart, especially if you have heart disease. If you have chest pain during sexual activity, call your doctor immediately and avoid sexual activity until your doctor tells you otherwise.
• tell all your health care providers that you are taking tadalafil. If you ever need emergency medical treatment for a heart problem, the health care providers who treat you will need to know when you last took tadalafil.

What special dietary instructions should I follow?

Talk to your doctor about drinking grapefruit juice while taking this medicine.

What side effects can this medication cause?

Tadalafil may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• headache
• indigestion or heartburn
• flushing
• pain in the back, muscles, or any limb
• stuffy or runny nose

Some side effects can be serious. The following symptoms are uncommon, but if you experience any of them, call your doctor immediately:

• erection that lasts longer than 4 hours
• changes in vision (seeing a blue tinge on objects or having difficulty telling the difference between blue and green)
• chest pain

Tadalafil may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

What storage conditions are needed for this medicine?

Keep this medication 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.

In case of emergency/overdose

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

Symptoms of overdose may include:

• headache
• indigestion or heartburn
• flushing
• pain in the back, muscles, or any limb
• stuffy or runny nose
• erection that lasts longer than 4 hours

What other information should I know?

Keep all appointments with your doctor .

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.