Viagra is taken by mouth as needed between four hours and one-half hour before sexual activity (about one hour before is most effective). Take only as directed, usually once daily as needed. Sildenafil works along with sexual stimulation to help achieve an erection.
Headache, flushing, stomach upset, nasal stuffiness, diarrhea and dizziness might occur. If these effects persist or worsen, notify your doctor promptly.
If you have heart problems severe enough to make sexual activity a danger, you should avoid using
Viagra. Use it cautiously---if at all---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 (crushing heart pain that occurs at any time). 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 this medication with caution. Its safety under these circumstances has not yet been studied. Remember that
Viagra offers no protection from transmission of sexually transmitted diseases, such as HIV, the virus that causes AIDS. This drug is not for use by women. Its effects during pregnancy have not been studied. Before using this drug, tell your doctor your medical history, including any allergies (especially drug allergies), any penis conditions such as fibrosis/scarring, history of painful/prolonged erection (priapism), sickle cell anemia, blood system cancers (such as leukemia or myeloma), or Peyronie's disease, eye problems (retina diseases). kidney or liver disease, bleeding disorders or active stomach ulcers, heart diseases, stroke or severe high or low blood pressure. Limit alcohol intake, as it may aggravate side effects of
Viagra. To avoid dizziness and lightheadedness when rising from a seated or lying position, get up slowly. The elderly may be more sensitive to the side effects of
Viagra, therefore caution is advised in this group.
If
Viagra is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining
Viagra with the following: Other impotence remedies including Caverject and Muse, Amlodipine (Norvasc), Cimetidine (Tagamet), Erythromycin (E-Mycin, Ery-Tab, PCE), Itraconazole (Sporanox), Ketoconazole (Nizoral). Do not take
Viagra if you are taking any nitrate-based drug, Nitrates such as Isordil, Nitro-Bid, Transderm-Nitro, Nitrol and Nitro-Dur, nitroglycerin pills (Nitro-Bid, Nitrostat) and isosorbide pills (Dilatrate-SR, Isordil, Sorbitrate), Rifampin (Rifadin, Rimactane), Ritonavir (Norvir), Saquinavir (Fortovase, Invirase). Combining
Viagra with these drugs can cause a severe drop in blood pressure. If
Viagra gives you an allergic reaction, do not use it again. Tell your doctor of all nonprescription and prescription medication you may use, especially any nitrate medications (e.g., nitroglycerin, isosorbide dinitrate), nitroprusside (any "nitric oxide donor" medicines), cimetidine, erythromycin, azole antifungals (e.g., itraconazole, ketoconazole), mibefradil, rifamycins (e.g., rifampin) or high blood pressure medicines.
No overdose of
Viagra has been reported. However, any medication taken in excess can have serious consequences. If you suspect an overdose, seek medical attention immediately.
