What is the most important information I should know about Cialis?

Do not take Cialis if you are also using a nitrate drug for chest pain or heart problems. This includes nitroglycerin (Nitrostat, Nitro-Dur, Nitrolingual, 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 Cialis 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, or have pain, numbness, or tingling in your chest, arms, neck, or jaw during sexual activity, stop and call your doctor right away. You could be having a serious side effect of Cialis.

Do not take Cialis 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.

A small number of patients have had a sudden loss of eyesight after taking Cialis. This type of vision loss is caused by decreased blood flow to the optic nerve of the eye. It is not clear whether Cialis is the actual cause of such vision loss. Sudden vision loss with Cialis use has occurred most often in people with 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.

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

What is Cialis?

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

Cialis is used to treat erectile dysfunction (impotence).

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

What should I discuss with my healthcare provider before taking Cialis?

Do not take Cialis 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 Cialis with a nitrate medicine can cause a serious decrease in blood pressure, leading to fainting, stroke, or heart attack.

A small number of patients have had a sudden loss of eyesight after taking Cialis. This type of vision loss is caused by decreased blood flow to the optic nerve of the eye. It is not clear whether Cialis is the actual cause of such vision loss. Sudden vision loss with Cialis use has occurred most often in people with 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.

Before taking Cialis, tell your doctor if you have:

heart disease or heart rhythm problems;

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

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

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.

If you have any of these conditions, you may not be able to use Cialis or you may need a dosage adjustment or special tests during treatment.

FDA pregnancy category B: Although Cialis is not for use in women, this medication is not expected to be harmful to an unborn baby. Do not use Cialis without telling your doctor if you are pregnant or plan to become pregnant during treatment.

Although Cialis is not for use in women, it is not known if Cialis passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

You may need a lower dose of this medication if you are older than 65. Follow your doctor's instructions.

How should I take Cialis?

Take Cialis exactly as it was prescribed for you. Do not take it in larger doses or for longer than recommended by your doctor.

Take each dose with a full glass of water.

Cialis can be taken with or without food.

Cialis is usually taken only when needed, just before sexual activity. The medication 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 Cialis 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.

Store this medication at room temperature away from moisture and heat.

What happens if I miss a dose?

Since Cialis is used as needed, you are not likely to be on a dosing schedule.

What happens if I overdose?

Seek emergency medical attention if you think you have used too much of this medicine.

Symptoms of a Cialis overdose may include chest pain, nausea, irregular heartbeat, and feeling light-headed or fainting.

What should I avoid while taking Cialis?

Avoid drinking alcohol, which can increase some of the side effects of Cialis.

Grapefruit and grapefruit juice may interact with Cialis. 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.

Do not use any other drug to treat impotence, such as alprostadil (Caverject, Muse, Edex) or yohimbine (Yocon, Yodoxin, others), unless your doctor tells you to.

What are the possible side effects of Cialis?

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

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

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.

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

chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, general ill feeling;

swelling in your hands, ankles, or feet;

shortness of breath;

irregular heartbeat;

vision changes;

feeling light-headed, fainting; or

penis erection that is painful or lasts 4 hours or longer.

Continue taking Cialis and talk with your doctor if you have any of these less serious side effects:

warmth or redness in your face, neck, or chest;

headache;

stuffy nose;

upset stomach; or

back pain.

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.

What other drugs will affect Cialis?

Before taking Cialis, tell your doctor if you are using any of the following 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).

If you are using any of these drugs, you may not be able to take Cialis, or you may need dosage adjustments or special tests during treatment.

There may be other drugs not listed that can affect Cialis. 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.