Know the basics
What is sildenafil used for?
Sildenafil is used to treat high blood pressure in the lungs (pulmonary hypertension). It works by relaxing and widening the blood vessels in your lungs which allows the blood to flow more easily. Decreasing high blood pressure in the lungs allows your heart and lungs to work better and improves your ability to exercise.
This medication is not recommended for use in children. Discuss the risks and benefits of this medication with the doctor.
OTHER USES: This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.
Sildenafil is also available in other brands and other strengths to treat erectile dysfunction-ED in men. Do not take this medication with any other product that contains sildenafil or other similar medications for erectile dysfunction-ED or pulmonary hypertension (such as tadalafil, vardenafil).
How should I take sildenafil?
Read the Patient Information Leaflet and Instructions for Use if available from your pharmacist before you start sildenafil and each time you get a refill. If you have any questions, ask your doctor or pharmacist.
To treat high blood pressure in the lungs, take this medication by mouth with or without food as directed by your doctor, usually 3 times a day (about 4-6 hours apart). The dosage is based on your medical condition, response to treatment, and other medications you may be taking. Be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).
Do not increase your dose or take this drug more often than prescribed. Your condition will not improve any faster, and your risk of side effects will increase.
This medication is mixed by your pharmacist. Shake the bottle well for 10 seconds before each dose. Carefully measure the dose using the measured oral syringe that comes with this medication. Do not use a household spoon because you may not get the correct dose.
Do not mix with any other medications/liquids.
Take sildenafil regularly to get the most benefit from it. To help you remember, take it at the same times each day.
Tell your doctor if your condition does not improve or if it worsens.
How do I store sildenafil?
Store at room temperature away from light and moisture. Do not store in the bathroom. Do not freeze. Different brands of this medication may have different storage needs. Check the product package for instructions on how to store your brand, or ask your pharmacist. Keep all medicines away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.
Know the precautions & warnings
What should I know before using sildenafil?
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
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.
Stop using sildenafil and call your doctor at once if you have a serious side effect such as:
- sudden vision loss;
- ringing in your ears, or sudden hearing loss;
- chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, general ill feeling;
- irregular heartbeat;
- swelling in your hands, ankles, or feet;
- shortness of breath;
- vision changes;
- feeling light-headed, fainting; or
- penis erection that is painful or lasts 4 hours or longer.
Less serious side effects may include:
- warmth or redness in your face, neck, or chest;
- stuffy nose;
- memory problems;
- upset stomach; or
- back pain
Is it safe to take sildenafil during pregnancy or breast-feeding?
There are no adequate studies in women for determining risk when using this medication during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking this medication. This medication is pregnancy risk category B. (A=No risk, B=No risk in some studies, C=There may be some risk, D=Positive evidence of risk, X=Contraindicated, N=Unknown)
Know the side effects
What are the side effects of sildenafil?
Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.
Know the interactions
What drugs may interact with sildenafil?
Sildenafil may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.
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. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
- Amyl Nitrite
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Eslicarbazepine Acetate
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Does food or alcohol interact with sildenafil?
Sildenafil may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.
What health conditions may interact with sildenafil?
Sildenafil may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have.
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Abnormal penis, including a curved penis or birth defects or
- Angina (chest pain) or
- Arrhythmia (irregular heartbeat), within the last 6 months or
- Bleeding problem, history of or
- Coronary artery disease or
- Heart attack (within the last 6 months) or
- Heart disease or
- Hypertension (high blood pressure) or
- Hypotension (low blood pressure) or
- Leukemia (type of blood cancer) or
- Multiple myeloma (bone marrow cancer) or
- Priapism, history of or
- Retinitis pigmentosa (an inherited eye disorder) or
- Sickle-cell anemia (blood disorder) or
- Stomach ulcer, history of or
- Stroke (within the last 6 months)—Use with caution. May cause side effects to become worse.
- Age greater than 50 years or
- Coronary artery disease or
- Crowded disc or low cup to disc ratio in the eye (an eye disorder) or
- Diabetes or
- Heart disease or
- Hyperlipidemia (high fats in the blood) or
- Hypertension (high blood pressure) or
- Non-arteritic anterior ischemic optic neuropathy or NAION (serious eye condition), history of or
- Smoking—May increase the chance for a serious side effect in the eye called NAION.
- Pulmonary veno-occlusive disease or PVOD (a type of lung disease)—May make this condition worse.
Understand the dosage
The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using this Sildenafil.
What is the dose of Sildenafil for an adult?
Usual Adult Dose for Erectile Dysfunction:
Initial dose: 50 mg orally once a day, as needed, 1 hour prior to sexual activity
Maintenance: 25 to 100 mg orally once a day, as needed, 1 hour prior to sexual activity
Comments: This drug may be taken anywhere from 30 minutes to 4 hours before sexual activity.
Usual Adult Dose for Pulmonary Hypertension:
- Initial dose: 5 or 20 mg orally three times a day, 4 to 6 hours apart
- Maximum dose: 20 mg orally three times a day
- Initial dose: 2.5 or 10 mg IV bolus three times a day
- No greater efficacy was achieved with oral doses higher than the maximum recommended dose.
- A 10 mg injection dose is predicted to provide pharmacological effect equivalent to the 20 mg oral dose.
Usual Geriatric Dose for Erectile Dysfunction:
Initial dose: 25 mg orally once a day 1 hour prior to sexual activity
What is the dose of Sildenafil for a child?
Safety and effectiveness have not been established in pediatric patients (less than 18 years of age).
How is Sildenafil available?
Sildenafil is available in the following dosage forms and strengths:
Tablet 20 mg; 25 mg; 50 mg; 100 mg
Injection 10 mg/12,5 mL
Powder, oral suspension 10 mg/mL
What should I do in case of an emergency or overdose?
In case of an emergency or an overdose, call your local emergency services (115) or go to your nearest emergency room.
What should I do if I miss a dose?
If you miss a dose of Sildenafil, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.
Hello Health Group does not provide medical advice, diagnosis or treatment.
Review Date: May 30, 2016 | Last Modified: January 4, 2017
Sildenafil https://www.drugs.com/cdi/sildenafil.html. Accessed July 26, 2016.
Sildenafil https://medlineplus.gov/druginfo/meds/a699015.html. Accessed July 26, 2016.
Sildenafil http://patient.info/medicine/sildenafil-for-erectile-dysfunction-nipatra-viagra-vizarsin. Accessed July 26, 2016.