PRECAUTIONS:

Before taking sildenafil, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. Before using this medication, tell your doctor or pharmacist your medical history, especially of: penis conditions (e.g., angulation, fibrosis/scarring, Peyronie's disease), history of painful/prolonged erection (priapism), sickle cell anemia, blood system cancers (e.g., leukemia or myeloma), eye problems (e.g., retina diseases like retinitis pigmentosa), kidney disease, liver disease, bleeding disorders, active stomach ulcers, heart problems (e.g., recent heart attack or serious arrhythmia within past 6 months, heart failure, coronary artery disease with unstable angina, aortic stenosis, idiopathic hypertrophic subaortic stenosis), recent stroke within past 6 months, very high or low blood pressure. This drug may make you dizzy or cause vision changes; use caution engaging in activities requiring alertness such as driving or using machinery. Limit alcoholic beverages. To minimize dizziness and lightheadedness, get up slowly when rising from a seated or lying position. Caution is advised when using this drug in the elderly because they may be more sensitive to the side effects of the drug. This drug is not indicated for use in women or children.

HOW TO USE:

This drug is taken by mouth as needed, at least 30 minutes, but no more than 4 hours, before sexual activity (1 hour before is the most effective). Do not take more often than once daily, and take as directed. A high fat meal may delay the time of onset of this drug. Avoid eating grapefruit or drinking grapefruit juice while you are being treated with this medication unless your doctor instructs you otherwise. The dosage is based on your medical condition, response to therapy, and other medications you may be taking (see also Drug Interactions section). Consult your doctor or pharmacist for more details.

DOSING:

Sildenafil is rapidly absorbed. Maximum observed plasma concentrations are reached within 30 to 120 minutes (median 60 minutes) of oral dosing in the fasted state. When sildenafil is taken with a high fat meal, the rate of absorption is reduced, with an average delay in the time to maximal concentration of 1 hour.

Side effects

In clinical trials, the most common adverse effects of sildenafil use included headache, flushing, dyspepsia, nasal congestion and impaired vision, including photophobia and blurred vision. Some sildenafil users have complained of seeing everything tinted blue (cyanopsia). Some complained of blurriness and loss of peripheral vision. In July 2005, the U.S. Food and Drug Administration found that sildenafil could lead to vision impairment in rare cases and a number of studies have linked sildenafil use with nonarteritic anterior ischemic optic neuropathy.

DRUG INTERACTIONS:

See also How To Use section for drug-food interactions. This drug should not be used with the following medications because very serious (possibly fatal) interactions may occur: nitrates (e.g., nitroglycerin, isosorbide), nitroprusside (or any "nitric oxide donor" drugs), recreational drugs called "poppers" containing amyl or butyl nitrite. If you are currently using any of these medications, tell your doctor or pharmacist before starting sildenafil. Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription products you may use, especially of: other medications for impotence, azole antifungals (e.g., itraconazole, ketoconazole), cimetidine, erythromycin, mibefradil, rifamycins (e.g., rifampin), high blood pressure medicines, delavirdine. If you are taking an HIV protease inhibitor (e.g., ritonavir, saquinavir), do not take more than a 25mg dose of sildenafil in a 48 hour period. If you are taking more than a 25mg dose of sildenafil and are also taking an alpha-blocker medication (e.g., doxazosin, prazosin, terazosin) for various conditions (e.g., enlarged prostate), separate the time between taking these medications by more than 4 hours. Do not start or stop any medicine without doctor or pharmacist approval.

STORAGE:

Store at room temperature at 77 degrees F (25 degrees C) away from light and moisture. Brief storage between 59 and 86 degrees F (15-30 degrees C) is permitted. Do not store in the bathroom. Keep all medicines away from children and pets.