Cialis relaxes muscles and increases blood flow to particular areas of the body. It is a phosphodiesterase inhibitor.

Cialis is used to treat erectile dysfunction (impotence). It works by helping to increase blood flow into the penis during sexual stimulation. This helps you to achieve and maintain an erection.

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

Do not take Cialis if you are also using a nitrate drug for chest pain or heart problems, including nitroglycerin (Nitrostat, Nitrolingual, Nitro-Dur, Nitro-Bid, Minitran, Deponit, Transderm-Nitro), isosorbide dinitrate (Dilatrate-SR, Isordil, Sorbitrate), and isosorbide mononitrate (Imdur, ISMO, Monoket), or 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 have certain conditions, you may need a dose adjustment or special tests to safely take Cialis. Before taking this medication, tell your doctor if you are allergic to any drugs, or if you have:

• 1. Heart disease or heart rhythm problems;
• 2. A recent history a heart attack (within the past 90 days);
• 3. A recent history of stroke or congestive heart failure (within the past 6 months);
• 4. Angina (chest pain);
• 5. High or low blood pressure;
• 6. Liver disease;
• 7. Kidney disease (or if you are on dialysis);
• 8. A blood cell disorder such as sickle cell anemia, multiple myeloma, or leukemia;
• 9. A bleeding disorder such as hemophilia;
• 10. A stomach ulcer;
• 11. Retinitis pigmentosa (an inherited condition of the eye);
• 12. A physical deformity of the penis (such as Peyronie's disease); or
• 13. If you have been told you should not have sexual intercourse for health reasons.

This medication 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 Cialis, 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 Cialis is the actual cause of vision loss. Stop using Cialis and get emergency medical help if you have sudden vision loss.

Take Cialis 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.

Cialis can be taken with or without food.
This medication is usually taken only when needed, just before sexual activity. However, Cialis may also be taken daily (at a lower dose), regardless of when sexual activity is planned. Follow your doctor's instructions.

Cialis can help achieve an erection when sexual stimulation occurs. An erection will not occur just by taking a pill. Follow your doctor's instructions.

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

If you take Cialis 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.

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.

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.

Avoid using other medicines to treat impotence, such as alprostadil (Caverject, Muse, Edex) or yohimbine (Yocon, Yodoxin, others), without first talking to your doctor.

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. During sexual activity, if you become dizzy or nauseated, or 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 Cialis.

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

• 1. Sudden vision loss;
• 2. Ringing in your ears, or sudden hearing loss;
• 3. Chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, general
           ill feeling;
• 4. Irregular heartbeat;
• 5. Swelling in your hands, ankles, or feet;
• 6. Shortness of breath;
• 7. Vision changes;
• 8. Seizure (convulsions);
• 9. Feeling light-headed, fainting; or
• 10. Penis erection that is painful or lasts 4 hours or longer.

Less serious Cialis side effects may include:

• 1. Warmth or redness in your face, neck, or chest;
• 2. Stuffy nose, sore throat;
• 3. Headache;
• 4. Memory problems;
• 5. Diarrhea, upset stomach; or
• 6. Muscle pain, back pain.

Do not take Cialis if you are also using a nitrate drug for chest pain or heart problems, including nitroglycerin (Nitrostat, Nitrolingual, Nitro-Dur, Nitro-Bid, Minitran, Deponit, Transderm-Nitro), isosorbide dinitrate (Dilatrate-SR, Isordil, Sorbitrate), and isosorbide mononitrate (Imdur, ISMO, Monoket), or recreational drugs such as amyl nitrate or nitrite ("poppers").