This article describes possible interactions with sildenafil oral tablet. Interactions can cause a drug to have a different effect on the body than expected. Interactions can occur due to medications, alcohol, or certain health conditions.
Sildenafil comes as tablets that you’ll swallow. It’s also available as a solution that’s injected into your vein and a suspension (type of liquid) that’s swallowed. Interactions and uses of sildenafil may vary depending on the form of sildenafil you’re prescribed.
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Other drugs and sildenafil
The drugs in the list below may interact with sildenafil oral tablet. This article doesn’t include all drugs that may interact with sildenafil. Talk with your doctor about drugs not to take with Viagra or Revatio, sildenafil’s brand-name versions.*
Drug classes or drugs that may interact with sildenafil oral tablet include:
- nitrates:
- drug examples: nitroglycerin (Nitrostat, others), isosorbide mononitrate
- what might happen: can increase the risk of side effects of the nitrate
- certain blood pressure medications:
- guanylate cyclase stimulators:
- drug example: riociguat (Adempas)
- what might happen: can increase the risk of side effects of the guanylate cyclase stimulator
- certain HIV medications:
- drug examples: ritonavir (Norvir), atazanavir (Reyataz)
- what might happen: can increase the risk of side effects of sildenafil
- certain antifungals:
- drug examples: ketoconazole, itraconazole (Sporanox, others)
- what might happen: can increase the risk of side effects of sildenafil
- certain antibiotics:
- drug examples: clarithromycin, erythromycin
- what might happen: can increase the risk of side effects of sildenafil
- monoamine oxidase inhibitors (MAOIs):
- drug example: phenelzine (Nardil)
- what might happen: can increase the risk of side effects of sildenafil and the MAOI
- nefazodone:
- what might happen: can increase the risk of side effects of sildenafil
- carbamazepine (Tegretol, others):
- what might happen: can make sildenafil less effective
- amlodipine (Norvasc):
- what might happen: can increase the effect of amlodipine and increase the risk of side effects of sildenafil
* A generic medication is an identical copy of the active ingredient in a brand-name medication. (An active ingredient is what makes a medication work.)
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Get free cardOther interactions and sildenafil
Interactions can occur with supplements, foods, vaccines, and some lab tests. Below you can learn whether sildenafil oral tablet has these interactions.
The information below doesn’t include all other possible interactions with sildenafil.
Sildenafil and supplements
Before taking sildenafil oral tablet, tell your doctor and pharmacist about any herbs you take, as well as vitamins and supplements. Doing so may help you avoid interactions.
If you have questions about interactions that may affect you, talk with your doctor or pharmacist.
Sildenafil interactions with herbs
Sildenafil oral tablet may interact with St. John’s wort. This herb is often used to ease symptoms of depression. But taking sildenafil and St. John’s wort may make sildenafil less effective.
Because of this, ask your doctor or pharmacist before taking any of these products while taking sildenafil oral tablet.
Sildenafil interactions with vitamins
Sildenafil oral tablet isn’t known to interact with any vitamins. But this doesn’t mean interactions with vitamins can’t happen or won’t be identified later.
Because of this, ask your doctor or pharmacist before using any of these products while taking sildenafil oral tablet.
Sildenafil and food
Sildenafil oral tablet may interact with grapefruit and grapefruit juice. If you take sildenafil with these, an interaction could increase the level of the drug in your body. This may increase the risk of side effects from sildenafil.
Because of this, talk with your doctor or pharmacist if you have questions about sildenafil interactions with food.
Sildenafil and vaccines
Sildenafil oral tablet isn’t known to interact with any vaccines. But this doesn’t mean interactions with vaccines can’t happen or won’t be identified later.
Because of this, talk with your doctor or pharmacist before receiving any vaccines while taking sildenafil oral tablet.
Sildenafil and lab tests
Sildenafil oral tablet isn’t known to interact with lab tests. But this doesn’t mean interactions with lab tests can’t happen or won’t be identified later.
Because of this, talk with your doctor or pharmacist before having any tests while taking sildenafil oral tablet.
Sildenafil and cannabis or CBD
Studies of cannabis (commonly called marijuana) and cannabis products have been shown to interact with sildenafil. Cannabidiol (CBD) is an example of a cannabis product.
Taking sildenafil and using cannabis may lead to increased sildenafil levels in your body. This can raise your risk of side effects from sildenafil.
Before you take sildenafil, tell your doctor and pharmacist if you use cannabis. Doing so may help prevent possible interactions.
Note: Cannabis is illegal at a federal level but is legal in many states to varying degrees.
Alcohol and sildenafil
Sildenafil oral tablet is known to interact with alcohol. Taking sildenafil oral tablet and drinking alcohol may increase your risk of low blood pressure.
Talk with your doctor if you have concerns about sildenafil interactions with alcohol.
When to avoid sildenafil
Certain health conditions or other factors could increase some risks with sildenafil oral tablet. Because of this, doctors may not prescribe sildenafil in these cases. These health conditions or other factors are called contraindications.
Here’s a list of contraindications for sildenafil oral tablet:
- Use of nitrates. If you take a nitrate medication, taking sildenafil oral tablet may increase the risk of severely low blood pressure. (Nitrates are certain drugs used to treat chest pain.)
- Use of guanylate cyclase stimulators. If you take a guanylate cyclase stimulator medication, taking sildenafil oral tablet may increase the risk of severely low blood pressure. (Guanylate cyclase stimulators are drugs used to treat high blood pressure in the lungs.)
- Past allergic reaction to sildenafil. If you’ve ever had an allergic reaction to sildenafil oral tablet, taking it again may cause another allergic reaction.
Before you start taking sildenafil, tell your doctor if anything listed above relates to you. They can recommend whether you should take sildenafil.
Health factors and sildenafil
Certain medical conditions or other health factors may increase the risk of interactions with sildenafil oral tablet. Keep in mind that interactions could lead to side effects or affect how well the drug works. Before taking sildenafil, tell your doctor about your health history. They’ll determine whether sildenafil is right for you.
These health conditions or other factors might interact with sildenafil oral tablet:
- heart problems, including heart surgery within the last 6 months
- high blood pressure in the lungs
- history of stroke
- unmanaged high or low blood pressure
- irregular penis shape
- past erections that have lasted longer than 4 hours
- abnormal blood cell levels
- eye problems
- bleeding problems
- past stomach ulcers
- kidney problems
- liver problems
- pregnancy or breastfeeding
- past allergic reaction to sildenafil
Preventing sildenafil interactions
You may be able to help avoid certain interactions with sildenafil oral tablet. Before taking this drug, you may want to discuss possible interactions with your doctor and pharmacist.
Things to consider include:
- Whether you drink alcohol or use cannabis.
- Other medications and herbs you take, as well as vitamins and supplements. Your doctor or pharmacist can help you fill out a medication list.
- What to do if you’re prescribed a new drug while taking sildenafil oral tablet.
Taking sildenafil exactly as prescribed can also help prevent interactions.
What to ask your doctor
If you have questions about sildenafil and possible interactions, talk with your doctor.
Questions you may want to ask your doctor include:
- Can I still take sildenafil if it interacts with a health condition I have?
- How do the interactions of sildenafil compare with those of other drugs used for my condition?
- Should I tell you if I start taking another medication or supplement during my sildenafil treatment?
Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.