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 should I discuss with my doctor before taking 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. A small number of patients have had a sudden loss of eyesight after taking tadalafil. This type of vision loss is caused by decreased blood flow to the optic nerve of the eye. It is not clear whether tadalafil is the actual cause of such vision loss. Sudden vision loss with tadalafil 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 tadalafil, 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 tadalafil or you may need a dosage adjustment or special tests during treatment. FDA pregnancy category B: Although tadalafil is not for use in women, this medication is not expected to be harmful to an unborn baby. Do not use tadalafil without telling your doctor if you are pregnant or plan to become pregnant during treatment. Although tadalafil is not for use in women, it is not known if tadalafil 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 tadalafil? Take each dose with a full glass of water. Avoid taking High-fat food before taking Viagra as it may cause the medicine to take more time to start working. Tadalafil is usually taken only when needed, 30 - 60 minutes before sexual activity. The medication can help achieve an erection when sexual stimulation occurs. An erection will not occur just by taking a pill. Do not take tadalafil more than once a day. Allow 24 hours to pass between doses. 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. What happens if I overdose? Seek emergency medical attention if you think you have used too much of this medicine. Symptoms of a tadalafil overdose 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. 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 tadalafil? 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 tadalafil. Stop using tadalafil 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 tadalafil 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; irregular heartbeat; swelling in your hands, ankles, or feet; shortness of breath; vision changes; feeling light-headed, fainting; or penis erection that is painful or lasts 4 hours or longer. Continue taking tadalafil and talk with your doctor if you have any of these less serious side effects: warmth or redness in your face, neck, or chest; stuffy nose; headache; 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 drug(s) may interact with tadalafil? Do not take tadalafil if you are taking the following medications: nitroglycerin-type drugs for the heart or chest pain such as amyl nitrite, isosorbide dinitrate, isosorbide mononitrate, nitroglycerin, even if these are only taken occasionally Tadalafil may also interact with the following medications: alpha blockers, such as alfuzosin (UroXatral®), doxazosin (Cardura®), prazosin (Minipress®), or terazosin (Hytrin®), used to treat high blood pressure or an enlarged prostate. bosentan certain antibiotics such as clarithromycin, erythromycin, troleandomycin certain drugs used for seizures such as carbamazepine, phenytoin, and phenobarbital cimetidine cisapride diltiazem grapefruit juice medicines for fungal infections (fluconazole, itraconazole, ketoconazole, voriconazole) mibefradil nicardipine certain medicines for the treatment of HIV infection or AIDS quinidine rifabutin, rifampin or rifapentine some drugs for treating depression, anxiety or other mood problems (examples: fluoxetine, fluvoxamine, nefazodone) verapamil What is the shelf life of the pills? The expiry date is mentioned on each blister. It is different for different batches. The shelf life is 2 years from the date of manufacture and would differ from batch to batch depending on when they were manufactured.