In the U.S.—

In Canada—

• Impotence therapy agent (systemic)

Sildenafil (sil-DEN-a-fil) belongs to a group of medicines that delay the enzymes called phosphodiesterases from working too quickly. The penis is one of the areas where these enzymes work. Sildenafil is used to treat men who have erectile dysfunction (also called sexual impotence).

By controlling the enzyme phosphodiesterase, sildenafil helps to maintain an erection that is produced when the penis is stroked. Without physical action to the penis, such as that occurring during sexual intercourse, sildenafil will not work to cause an erection.

VIAGRA is available only with your doctor's prescription, in the following dosage form(s):

Oral
• Tablets (U.S.)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For sildenafil, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to sildenafil. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Sildenafil is not indicated for use in women. Sildenafil has not been studied in pregnant women. However, sildenafil has not been shown to cause birth defects or other problems in animal studies.

Breast-feeding—It is not known whether sildenafil passes into breast milk. Sildenafil is not indicated for use in women.

Older adults—Elderly people are especially sensitive to the effects of sildenafil, which may increase their chance of having side effects. Patients 65 years of age and older are started on a low dose, 25 mg, of sildenafil. The dose may be increased by a doctor as needed and tolerated.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking sildenafil, it is especially important that your health care professional know if you are taking any of the following:

• Cimetidine (e.g., Tagamet)
• Erythromycin (e.g., E.E.S. or Ery-Tab)
• Itraconazole (e.g., Sporanox)
• Ketaconazole (e.g., Nizoral)
• Mibefradil (e.g., Posicor)
• Ritonavir (e.g., Norvir)
• Saquinavir (e.g., Fortovase or Invirase)—These medicines may increase the unwanted effects of sildenafil, unless lower starting doses of sildenafil are used

• Nitrates, such as nitroglycerin (e.g., Nitrostat or Transderm-Nitro)—Sildenafil increases the lowering of blood pressure by nitrates too much and their use together is not recommended

• Arrhythmias (irregular heartbeat) or
• Coronary artery disease or
• Heart attack, history of (within the last 6 months) or
• High blood pressure or
• Low blood pressure or
• Stroke, history of (within the last 6 months)—Chance of problems occurring may be increased

• Abnormal penis, including curved penis and birth defects of the penis—Chance of problems occurring may be increased

• Bleeding problems or
• Retinitis pigmentosa—Chance of problems occurring may be increased. It is not known if the medicine is safe for use in these patients

• Conditions causing thickened blood or slower blood flow, including leukemia; multiple myeloma (tumors of the bone marrow); or polycythemia, sickle cell disease, and thrombocythemia (blood problems) or
• Priapism (history of)—Although sildenafil does not cause priapism (erection lasting longer than 6 hours), patients with these conditions have an increased risk of priapism and it could occur while using sildenafil

• Heart or blood disease—Sexual activity increases the heart rate and blood flow and can increase the chance of problems occurring for some patients who use any type of medicine, including sildenafil, that increases sexual ability

• Kidney problems (severe) or
• Liver problems (severe)—Chance of problems occurring may be increased. Lower starting doses may be used and doses increased as needed and as tolerated

Special patient directions come with sildenafil. Read the directions carefully before using the medicine.

VIAGRA usually begins to work within 30 minutes after taking it. It continues to work for up to 4 hours, although its action is usually less after 2 hours.

Dosing—

The dose of sildenafil will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of sildenafil. If your dose is different, do not change it unless your doctor tells you to do so.

• For oral dosage form (tablets):
  • For treatment of erectile dysfunction:
    • Adults up to 65 years of age—50 mg as a single dose no more than once a day, 1 hour before sexual intercourse. Alternatively, the medicine may be taken 30 minutes to 4 hours before sexual intercourse. If needed, your doctor may increase your daily dose to 100 mg or decrease your daily dose to 25 mg.
    • Adults 65 years of age and older—25 mg as a single dose no more than once a day, 1 hour before sexual intercourse. Alternatively, the medicine may be taken 30 minutes to 4 hours before sexual intercourse. If needed, your doctor may increase your daily dose.
    • 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 Viagra in a 48 hour period

Storage—

To store VIAGRA:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Keep the medicine from freezing. Do not refrigerate.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.