Seek medical attention if prolonged erection (greater than four hours) occurs.
There is a potential risk of a cardiac event associated with sexual activity in some patients. This drug is not for use in such patients. Discuss these risks with your doctor prior to initiation of therapy.
May require lower doses in reduced kidney or liver function.
Inform your doctor if you have an anatomical deformation of the penis or conditions that may put you at an increased risk for priapism (prolonged, painful erections greater than six hours), including but not limited to sickle cell anemia, multiple myeloma, and leukemia.
Do not use nitrates in any form. See the following website for a list of such drugs (FDA). Check with your pharmacist or doctor before starting a new medication, herbal product or nonprescription drug while taking this drug.
Use with other erectile dysfunction treatments is not recommended.
DRUG INTERACTIONS
Nitrates (see cautions), alpha-blockers (such as doxazosin, terazosin, etc.), heparin, phenytoin, carbamazepine, phenobarbital, rifampin, antihypertensives, amlodipine, beta-blockers (such as propranolol, etc.), cimetidine, diuretics, ketoconazole, itraconazole, erythromycin, protease inhibitors, tacrolimus
This drug is metabolized by a specific set of liver enzymes (cytochrome P450 enzymes 3A4). Several other drugs interfere with these liver enzymes, and thus may increase or decrease the clearance of sildenafil from the body, potentially increasing the risk of side effects or decreasing effectiveness.
When these drugs are given in combination with sildenafil, dosage adjustments may be needed. As these are too numerous to list, you should always check with your doctor or pharmacist prior to starting a new medication, herbal, or nonprescription product.
PREGNANCY AND BREAST-FEEDING CAUTIONS
FDA Pregnancy Risk Category B. Not for use in women, and not recommended during breast-feeding.
SPECIAL INFORMATION
This medication is to be taken by mouth one hour prior to sexual activity. May be used anytime from four hours to 30 minutes before. Do not take sildenafil within four hours of taking an alpha-blocker (may result in significant low blood pressure). This drug does not protect against sexually transmitted diseases. Do not take more than once daily.
In 2005, the FDA reported a safety alert that described changes in the product labeling for all drugs in this class. Specifically, the changes were based on a small number of post-marketing reports of sudden vision loss, attributed to NAION
(non arteritis ischemic optic neuropathy), a condition where blood flow is blocked to the optic nerve. FDA advises patients to stop taking these medicines, and call a doctor or healthcare provider right away if they experience sudden or decreased vision loss in one or both eyes.
