annals internal medicine viagra

Viagra (Sildenafil)

Viagra is used to treat impotence in men. It increases the body's ability to achieve and maintain an erection during sexual stimulation.

Viagra should be taken as needed about 1 hour before sexual activity. However, Viagra can be taken anytime from 4 hours to 30 minutes before sexual activity.

Viagra is a phosphodiesterase inhibitor. It works by helping the blood flow into the penis to achieve and maintain an erection.

Viagra is used as needed, so you are not likely to miss a dose. If you miss a dose of Viagra, 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.

Keep Viagra in its original container. Store at 25 degrees C (77 degrees F); excursions permitted to 15-30 degrees C (59-86 degrees F).

Do not take Viagra if you are taking any nitrate-based drug, including nitroglycerin patches (Nitro-Dur, Transderm-Nitro), nitroglycerin ointment (Nitro-Bid, Nitrol), nitroglycerin pills (Nitro-Bid, Nitrostat), and isosorbide pills (Dilatrate-SR, Isordil, Sorbitrate). Combining Viagra with these drugs can cause a severe drop in blood pressure.

If you have heart problems severe enough to make sexual activity a danger, you should avoid using Viagra. Use it cautiously if you've had a heart attack, stroke, or life-threatening heart irregularities within the past 6 months. Be equally cautious if you have severe high or low blood pressure, heart failure, or unstable angina.

If you take Viagra and develop cardiac symptoms (for example, dizziness, nausea, and chest pain) during sexual activity, do not continue. Alert your doctor to the problem as soon as possible.

If you have a condition that might result in long-lasting erections, such as sickle cell anemia, multiple myeloma (a disease of the bone marrow), or leukemia, use Viagra with caution. Also use cautiously if you have a genital problem or deformity such as Peyronie's disease. If an erection lasts more than 4 hours, seek treatment immediately. Permanent damage and impotence could result.

If you have a bleeding disorder, a stomach ulcer, or the inherited eye condition known as retinitis pigmentosa, use Viagra with caution. Its safety under these circumstances has not yet been studied.

If you experience any of the following serious side effects, stop taking Viagra and seek emergency medical attention or notify your doctor immediately:

• an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives);
• chest pain or an irregular heartbeat;
• swelling of the ankles or legs;
• shortness of breath;
• prolonged or severe dizziness;
• a prolonged (lasting longer than 4 hours) or painful erection; or
• dizziness, nausea, or angina (pain, tightness, discomfort, numbness, or tingling in the chest, arms, neck, or jaw).

• flushing;
• mild dizziness;
• headache;
• nasal congestion;
• diarrhea;
• temporary blue tint in vision or other vision abnormalities; or
• itching or a rash.

If you are over 65 years of age, you may be more likely to experience side effects from Viagra. Your doctor may prescribe a lower dose of this medication.