How does Viagra work?

• Viagra increases blood flow to the penis allowing more blood flow into the penis like happened naturally when a man is sexually stimulated With more blood flowing in and less flowing out, the arteries in the penis enlarge resulting in an erection. If this mechanism is not working properly a man has difficulties in having and keeping en erection. Using Viagra a man can respond to sexual stimulation during a sexual encounter and once it is over the erection goes away.

What should I discuss with my doctor before taking Viagra?

• Do not take Viagra 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 Viagra 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 Viagra. This type of vision loss is caused by decreased blood flow to the optic nerve of the eye. It is not clear whether Viagra is the actual cause of such vision loss. Sudden vision loss with Viagra 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 Viagra, tell your doctor if you have:
  • heart disease or heart rhythm problems;
  • a recent history (in the past 6 months) of a heart attack, stroke, or heart rhythm disorder;
  • congestive heart failure;
  • high or low blood pressure;
  • coronary artery disease;
  • liver disease;
  • kidney disease;
  • 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 Viagra or you may need a dosage adjustment or special tests during treatment.
• FDA pregnancy category B: This medication is not expected to be harmful to an unborn baby. Do not use Viagra without telling your doctor if you are pregnant or plan to become pregnant during treatment.
• It is not known if Viagra 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.

How should I take Viagra?

• 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.
• Viagra is usually taken only when needed, 30 - 90 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 Viagra more than once a day. Allow 24 hours to pass between doses.
• Store this medication at room temperature away from moisture and heat.

How much Viagra can I take?

• Viagra comes in different doses (25 mg, 50 mg and 100 mg). If you do not get the results you expect, talk with your doctor. You and your doctor can determine the dose that works best for you.
• If you are older than age 65, or have serious liver or kidney problems, your doctor may start you at the lowest dose (25 mg) of Viagra. If you are taking protease inhibitors, such as for the treatment of HIV, your doctor may recommend a 25 mg dose and may limit you to a maximum single dose of 25 mg of Sildenafil citrate in a 48 hour period. If you are taking alpha-blocker therapy, you should not take a dose of greater than 25 mg of Viagra at the same time (within 4 hours) as your dose of alpha-blocker.

What happens if I miss a dose?

• Viagra is used as needed, so you are not likely to miss a dose.
• If you miss a dose of Revatio, take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the medicine at the next regularly scheduled time. 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. Symptoms of a Viagra overdose may include chest pain, nausea, irregular heartbeat, and feeling light-headed or fainting.

What should I avoid while taking Viagra?

• Avoid drinking alcohol, which can increase some of the side effects of Viagra.
• Avoid using other medicines to treat impotence, such as alprostadil (Caverject, Muse, Edex) or yohimbine (Yocon, Yodoxin, others), without first talking to your doctor.

What are the possible side effects of Viagra?

• 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 Viagra.
• Stop using Viagra 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 Viagra 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 Viagra 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.

Do not take Viagra 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

Viagra may also interact with the following medications:

• alpha blockers, used for high blood pressure or an enlarged prostate. NOTE: Do not take doses of Viagra higher than 25 mg within 4 hours of taking alpha blockers, such as alfuzosin (UroXatral®), doxazosin (Cardura®), prazosin (Minipress®), or terazosin (Hytrin®).
• bosentan
• certain drugs used for seizures such as carbamazepine, phenytoin, and phenobarbital
• certain drugs used for fungal or yeast infections, such as fluconazole, ketoconazole, and voriconazole
• certain drugs for the treatment of HIV infection or AIDS
• cimetidine
• cisapride
• clarithromycin
• diltiazem
• erythromycin
• grapefruit juice
• mibefradil
• nitroprusside
• rifabutin
• rifampin
• quinidine
• 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.