Our Health Library information does not replace the advice of a doctor. Please be advised that this information is made available to assist our patients to learn more about their health. Our providers may not see and/or treat all topics found herein.
What is the most important information I should know about oral sildenafil?
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 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 is sildenafil?
Sildenafil relaxes muscles of the blood vessels and increases blood flow to particular areas of the body.
Sildenafil under the name Viagra is used to treat erectile dysfunction (impotence) in men. Another brand of sildenafil is Revatio, which is used to treat pulmonary arterial hypertension and improve exercise capacity in men and women.
Do not take Viagra while also taking Revatio, unless your doctor tells you to.
Sildenafil may also be used for purposes not listed in this medication guide.
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, such as riociguat (Adempas).
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.
Tell your doctor if you are pregnant. It is not known whether this medicine will harm an unborn baby. However, having pulmonary arterial hypertension (PAH) during pregnancy may cause complications such as heart failure, stroke, or medical problems in both mother and baby. The benefit of treating PAH with Revatio may outweigh any risks to the baby.
It may not be safe to breast-feed while using this medicine. Ask your doctor about any risk.
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.
Revatio is usually taken three times each day, about 4 to 6 hours apart.
Viagra 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 Viagra more than once per day.
Shake the oral suspension (liquid) before you measure a dose. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).
Viagra 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 Viagra is used as needed, you are not likely to miss a dose.
If you miss a dose of Revatio, take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
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 are the possible side effects of oral sildenafil?
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.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What other drugs will affect oral sildenafil?
Do not take sildenafil with similar medications such as avanafil (Stendra), tadalafil (Cialis) or vardenafil (Levitra). Tell your doctor about all other medications you use for erectile dysfunction.
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. Not all possible drug interactions are listed here.
Where can I get more information?
Your pharmacist can provide more information about sildenafil.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.
Copyright 1996-2023 Cerner Multum, Inc. Version: 13.01. Revision date: 12/3/2018.