Do not take sildenafil if you are also using a nitrate drug for chest pain or heart problems, including nitroglycerin, isosorbide dinitrate, isosorbide mononitrate, and some recreational drugs such as "poppers". Taking sildenafil with a nitrate medicine can cause a sudden and serious decrease in blood pressure.
Some medicines can cause unwanted or dangerous effects when used with sildenafil. Tell your doctor about all your current medicines, especially riociguat (Adempas). Do not take sildenafil with riociguat.
Contact your doctor or seek emergency medical attention if your erection is painful or lasts longer than 4 hours. A prolonged erection (priapism) can damage the penis.
Stop using sildenafil and get emergency medical help if you have sudden vision loss.
Before taking this medicine
You should not use sildenafil if you are allergic to it, or:
if you take other medicines to treat pulmonary arterial hypertension, such as riociguat (Adempas).
Do not take this medicine if you are also using a nitrate drug for chest pain or heart problems. This includes nitroglycerin, isosorbide dinitrate, and isosorbide mononitrate. Nitrates are also found in some recreational drugs such as amyl nitrate or nitrite ("poppers"). Taking sildenafil with a nitrate medicine can cause a sudden and serious decrease in blood pressure.
To make sure sildenafil is safe for you, tell your doctor if you have ever had:
heart problems (chest pain, a heart rhythm disorder, heart attack);
high or low blood pressure;
blood circulation problems;
retinitis pigmentosa (an inherited condition of the eye);
blindness in one or both eyes;
bleeding problems;
a stomach ulcer;
pulmonary veno-occlusive disease (PVOD);
liver or kidney disease;
a blood cell disorder such as sickle cell anemia, multiple myeloma, or leukemia;
a physical deformity of the penis (such as Peyronie's disease); or
if you have been told you should not have sexual intercourse for health reasons.
Sildenafil can decrease blood flow to the optic nerve of the eye, causing sudden vision loss. This has occurred in a small number of people taking sildenafil, most of whom also had heart disease, diabetes, high blood pressure, high cholesterol, or certain pre-existing eye problems, and in those who smoked or were over 50 years old. It is not clear whether this medicine is the actual cause of vision loss.
This medicine is not expected to harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant. Women with pulmonary arterial hypertension should not stop taking sildenafil without talking to their doctor.
It is not known whether sildenafil passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby. Women with pulmonary arterial hypertension should not stop taking sildenafil without talking to their doctor.
Do not give this medication to anyone under 18 years old without medical advice.
