Generic Name: tadalafil (ta DAL a fil)
Brand Names: Cialis

What is tadalafil?
Tadalafil relaxes muscles and increases blood flow to particular areas of the body.
Tadalafil is used to treat erectile dysfunction (impotence).
Tadalafil may also be used for purposes other than those listed in this medication guide.

What is the most important information I should know about tadalafil?
Do not take tadalafil 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 tadalafil with a nitrate medicine can cause a serious decrease in blood pressure, leading to fainting, stroke, or heart attack. 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.

How should I take tadalafil?
Take tadalafil exactly as it was prescribed for you. Do not take it in larger doses or for longer than recommended by your doctor. Taking this medication in larger doses will not make it more effective, and could cause dangerous side effects.
Tadalafil can be taken with or without food.
Tadalafil is usually taken only when needed, just before sexual activity. However, tadalafil may also be taken daily (at a lower dose), regardless of when sexual activity is planned. Follow your doctor's instructions.
Tadalafil can help achieve an erection when sexual stimulation occurs. An erection will not occur just by taking a pill. Follow your doctor's instructions.
Do not take tadalafil more than once a day. Allow 24 hours to pass between doses. If you take the medication daily, take it at the same time each day. 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. Store this medication at room temperature away from moisture and heat.

What happens if I miss a dose?
Since tadalafil is used as needed, you are not likely to be on a dosing schedule.
If you take tadalafil every day and you miss a dose, take the missed dose as soon as you remember. If it is almost time for your next dose, wait until then to take the medicine and skip the missed dose. 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.
Overdose symptoms may include chest pain, nausea, irregular heartbeat, and feeling light-headed or fainting.

What should I avoid while taking tadalafil?
Avoid drinking alcohol, which can increase some of the side effects of tadalafil.
Grapefruit and grapefruit juice may interact with tadalafil. Discuss the use of grapefruit products with your doctor. Do not increase or decrease the amount of grapefruit products in your diet without first talking to your doctor.

Tadalafil side effects
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. 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.
Stop using tadalafil and call your doctor at once if you have any of these serious side effects:

• sudden vision loss;
• ringing in your ears, or sudden hearing loss;
• 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;
• seizure (convulsions);
• vision changes;
• feeling light-headed, fainting; or
• penis erection that is painful or lasts 4 hours or longer.

Less serious side effects may include:

• warmth or redness in your face, neck, or chest;
• stuffy nose, sore throat;
• headache;
• diarrhea, upset stomach; or
• muscle pain, back pain.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.

What other drugs will affect tadalafil?
Before taking tadalafil, tell your doctor about all other medications you use for erectile dysfunction, or if you are using any of the following medications:

• heart or blood pressure medications;
• cimetidine (Tagamet, Tagamet HB);
• erythromycin (E-Mycin, Eryc, Ery-Tab) or clarithromycin (Biaxin);
• doxazosin (Cardura), prazosin (Minipress), terazosin (Hytrin);
• HIV medicines such as amprenavir (Agenerase), tipranavir (Aptivus), darunavir (Prezista), efavirenz (Sustiva), nevirapine (Viramune), indinavir (Crixivan), saquinavir (Invirase, Fortovase), lopinavir/ritonavir (Kaletra), fosamprenavir (Lexiva), ritonavir (Norvir), atazanavir (Reyataz), or nelfinavir (Viracept);
• itraconazole (Sporanox) or ketoconazole (Nizoral);
• carbamazepine (Tegretol), phenobarbital (Luminal), or phenytoin (Dilantin); or
• rifampin (Rifadin, Rimactane).

This list is not complete and there may be other drugs that can interact with tadalafil. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

Where can I get more information?
Your pharmacist can provide more information about tadalafil.