Before Using viagra

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 for erectile dysfunction. Mothers who are taking this medicine for pulmonary arterial hypertension and who wish to breast-feed should discuss this with their doctor.

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 who are taking this medicine for erectile dysfunction are started on a low dose, 25 mg, of sildenafil. Patients who are taking this medicine for pulmonary arterial hypertension may also need to be started at a lower dose. 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:
Alpha-blockers (medicine for high blood pressure—Sildenafil when taken together with an alpha-blocker medicine may cause very low blood pressure. Sildenafil doses above 25 mg should not be taken within 4 hours of taking an alpha-blocker medicine.
Bosentan (e.g., Tracleer)—May increase amounts of bosentan in the body
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
Erectile dysfunction medicines—These medicines should not be used at the same time as sildenafil because the safety of using these medicines in combination has not been proven.
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

Other medical problems—The presence of other medical problems may affect the use of sildenafil. Make sure you tell your doctor if you have any other medical problems, especially:
Age greater than 50 years or
Coronary artery disease or
Diabetes or
Hyperlipidemia (excess of lipids in the blood) or
Hypertension (high blood pressure) or
Low cup to disc ratio (“crowded disc”) or
Smoking—These conditions may increase risk for a serious eye problem called NAION.
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
NAION (serious eye condition) in one or both eyes, previously—May increase your chance of getting NAION again.
Pulmonary veno-occlusive disease (high blood pressure in the blood vessels of the lungs)—May make heart problems worse in patients with this serious condition