Sildenafil relaxes muscles of the blood vessels and increases blood flow to particular areas of the body.
WHAT ARE THE POSSIBLE SIDE EFFECTS OF ORAL SILDENAFIL (REVATIO, VIAGRA)?
Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Stop taking sildenafil and get emergency medical help if you have:
- heart attack symptoms–chest pain or pressure, pain spreading to your jaw or shoulder, nausea, sweating;
- vision changes or sudden vision loss; or
- erection is painful or lasts longer than 4 hours (prolonged erection can damage the penis).
Call your doctor at once if you have:
- severe shortness of breath, cough with foamy mucus;
- ringing in your ears, or sudden hearing loss;
- irregular heartbeat;
- swelling in your hands, ankles, or feet;
- a seizure; or (convulsions); or
- a light-headed feeling, like you might pass out.
Common side effects may include:
- flushing (warmth, redness, or tingly feeling);
- headache, dizziness;
- abnormal vision (blurred vision, changes in color vision)
- runny or stuffy nose, nosebleeds;
- sleep problems (insomnia);
- muscle pain, back pain; or
- upset stomach.
WHAT IS THE MOST IMPORTANT INFORMATION I SHOULD KNOW ABOUT ORAL SILDENAFIL?
Some medicines can cause unwanted or dangerous effects when used with sildenafil.
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.
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.
WHAT SHOULD I DISCUSS WITH MY HEALTHCARE PROVIDER BEFORE TAKING ORAL SILDENAFIL?
You should not use sildenafil if you are allergic to it, or:
- if you take other medicines to treat pulmonary arterial hypertension,
Do not take sildenafil 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.
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 sildenafil is the actual cause of vision loss.
Do not give this medication to anyone under 18 years old without medical advice.
HOW SHOULD I TAKE ORAL SILDENAFIL?
Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.
Sildenafil is usually taken only when needed, 30 minutes to 1 hour before sexual activity. You may take it up to 4 hours before sexual activity. Do not take Sildenafil more than once per day.
Sildenafil can help you have an erection when sexual stimulation occurs. An erection will not occur just by taking a pill. Follow your doctor’s instructions.
During sexual activity, if you become dizzy or nauseated, or have pain, numbness, or tingling in your chest, arms, neck, or jaw, stop and call your doctor right away. You could be having a serious side effect of sildenafil.
Store at room temperature away from moisture and heat.
WHAT HAPPENS IF I MISS A DOSE?
Since Sildenafil is used as needed, you are not likely to miss a dose.
WHAT SHOULD I AVOID WHILE TAKING ORAL SILDENAFIL?
Drinking alcohol with this medicine can cause side effects.
Grapefruit may interact with sildenafil and lead to unwanted side effects. Avoid the use of grapefruit products.
Avoid using any other medicines to treat impotence, such as alprostadil or yohimbine, without first talking to your doctor.
WHAT OTHER DRUGS WILL AFFECT ORAL SILDENAFIL?
Tell your doctor about all your other medicines, especially:
- drugs to treat high blood pressure or a prostate disorder;
- antifungal medicine–ketoconazole or itraconazole; or
- medicine to treat HIV/AIDS–ritonavir and others.
This list is not complete. Other drugs may affect sildenafil, including prescription and over-the-counter medicines, vitamins, and herbal products.