Vardenafil and Warfarin: Can They Be Taken Together?

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Vardenafil and Warfarin: Understanding the Interaction

Published: 5 November 2026

Many men taking warfarin wonder whether vardenafil and warfarin can be used together safely. The good news is that vardenafil (generic Levitra) is not contraindicated with warfarin, and the two medicines can generally be prescribed together after careful assessment. However, because both medicines can affect bleeding risk and blood pressure, your prescriber will review your full medical history and current anticoagulation control before approving treatment.

What is vardenafil and warfarin used for?

Vardenafil is a prescription medicine used to treat erectile dysfunction (ED) in adult men [5]. It belongs to a group of medicines called PDE5 inhibitors, which work by relaxing blood vessels in the penis, allowing increased blood flow when you are sexually aroused. Vardenafil is available in 5mg, 10mg, and 20mg tablets, and is usually taken about 25 to 60 minutes before sexual activity. The medicine only works when you are sexually stimulated, and you should not take it more than once a day [5].

Warfarin is an anticoagulant (blood thinner) prescribed to prevent blood clots in conditions such as atrial fibrillation, deep vein thrombosis (DVT), pulmonary embolism, or after heart valve replacement. It works by blocking vitamin K, which your body needs to make clotting factors. Because warfarin affects how your blood clots, you will have regular blood tests (INR monitoring) to ensure your dose is correct and your blood is not too thin or too thick.

Erectile dysfunction is common in men taking warfarin, partly because the conditions requiring anticoagulation (such as heart disease or stroke) are also risk factors for ED [1]. Treating ED can significantly improve quality of life, and doing so safely alongside warfarin is an important consideration for many men.

Do vardenafil and warfarin interact with each other?

There is no major pharmacological interaction between vardenafil and warfarin that would prevent them being used together. Vardenafil does not significantly affect the way warfarin is broken down in the body, and warfarin does not substantially change vardenafil levels. Clinical studies have not identified a direct drug-to-drug interaction that would make the combination unsafe [5].

However, both medicines can have effects that require careful monitoring. Warfarin increases your risk of bleeding, and while vardenafil itself does not directly affect clotting, PDE5 inhibitors can lower blood pressure. If you are taking other medicines that also lower blood pressure or affect bleeding, the combined effect needs to be considered. Your prescriber will check your INR control, review all your current medicines, and ensure your warfarin dose is stable before prescribing vardenafil.

It is important to understand that 'no major interaction' does not mean 'no precautions needed'. Your prescriber will assess your individual cardiovascular health, the reason you are taking warfarin, and whether sexual activity is safe for you. Men with recent heart attack, stroke, unstable angina, or severe heart failure may be advised that sexual activity itself carries risk, regardless of the medicines involved [2].

How the interaction is managed in practice

When you request vardenafil through Cured Pharmacy's online consultation, our UK prescribers will ask about your warfarin therapy, including how long you have been taking it, your most recent INR result, and whether your dose is stable. If your anticoagulation is well controlled and you have no other contraindications, vardenafil can usually be prescribed safely. You will typically be started on the lowest effective dose (often 10mg) to minimise any risk of side effects such as dizziness or low blood pressure.

What your prescriber checks before approving vardenafil and warfarin together

During your online consultation, the prescriber will review several key factors to ensure vardenafil is safe for you. They will ask about your cardiovascular health, including any history of heart attack, stroke, angina, heart failure, or abnormal heart rhythms. Because warfarin is prescribed for conditions that often involve the heart or blood vessels, this assessment is particularly important [2].

Your prescriber will also check your current INR control and whether your warfarin dose has been stable. Frequent dose changes or INR results outside your target range may indicate that your anticoagulation is not yet optimally managed, and it may be safer to wait until it is stable before adding another medicine. They will review all your other medicines, including over-the-counter products and herbal supplements, to identify any additional interactions.

Certain medicines must never be taken with vardenafil, including nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, and recreational drugs known as 'poppers'. These combinations can cause a dangerous drop in blood pressure. Alpha-blockers (such as tamsulosin or doxazosin, often used for prostate symptoms) require caution and a lower starting dose of vardenafil. If you are taking any of these, your prescriber will discuss the safest approach [5].

Practical advice for taking vardenafil with warfarin safely

If your prescriber approves vardenafil, take it exactly as directed. Swallow the tablet whole with water about 25 to 60 minutes before you plan to have sex. You will need to be sexually aroused for the medicine to work. Do not take more than one dose in 24 hours, and do not increase your dose without consulting your prescriber [5].

Continue taking your warfarin exactly as prescribed, at the same time each day. Do not stop, change, or miss doses of warfarin without speaking to your anticoagulation clinic or GP, as this can increase your risk of clots or bleeding. Attend all your scheduled INR blood tests as usual. If you notice any unusual bruising, bleeding (such as blood in your urine or stools, nosebleeds that won't stop, or coughing up blood), contact your doctor immediately.

Be cautious with alcohol when taking vardenafil. Heavy drinking can worsen erectile dysfunction, increase the risk of side effects such as dizziness and low blood pressure, and interfere with warfarin control. Limit alcohol to moderate amounts and avoid drinking heavily before sex. Grapefruit juice can increase vardenafil levels in your blood and should be avoided.

What to do if you experience side effects

Common side effects of vardenafil include headache, flushing, indigestion, nasal congestion, and dizziness [5]. These are usually mild and temporary. If you feel dizzy or lightheaded, sit or lie down until it passes, and avoid driving or operating machinery. If side effects are troublesome or persistent, contact your prescriber, who may adjust your dose. Never stop taking warfarin because of side effects from vardenafil without medical advice.

Warning signs that need urgent medical attention

While serious side effects are rare, you should seek urgent help if you experience chest pain or discomfort during or after sex. Stop sexual activity immediately, sit down, and call 999 if the pain does not go away quickly. Do not take nitrate medicines (such as GTN spray) if you have used vardenafil in the past 24 hours, as this combination can be dangerous. Tell the paramedics or hospital staff that you have taken vardenafil [5].

An erection lasting more than four hours (priapism) is a medical emergency. If this happens, go to A&E straight away. Priapism can damage the penis permanently if not treated promptly. Sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing (sometimes with ringing in the ears or dizziness), are also emergencies. Stop taking vardenafil and seek immediate medical help [5].

If you notice signs of serious bleeding while taking warfarin—such as vomiting blood, black or tarry stools, severe headache, or a fall with head injury—seek urgent medical attention. These symptoms are related to warfarin rather than vardenafil, but it is important to be aware of them. Always carry your anticoagulant alert card and inform healthcare professionals that you are taking warfarin.

How to access vardenafil through Cured Pharmacy

Cured Pharmacy is a GPhC-registered online pharmacy (GPhC 9012511) offering convenient access to erectile dysfunction treatments, including vardenafil and warfarin combinations, after a clinical consultation. To request vardenafil, complete our online health questionnaire, providing accurate information about your warfarin therapy, INR control, cardiovascular health, and all current medicines. A UK-registered prescriber will review your answers and approve treatment only if it is safe and appropriate for you.

If approved, your vardenafil will be dispensed by our pharmacy team and delivered discreetly to your home. Vardenafil (generic Levitra) is available from £16.95, or £13.56 for first orders using code Ednew. We also offer other PDE5 inhibitors, including sildenafil (generic Viagra) from £0.45 (£0.36 with Ednew), tadalafil (generic Cialis) from £7.95 (£6.36 with Ednew), and Spedra (avanafil) from £20.95 (£16.76 with Ednew). Your prescriber will recommend the most suitable option based on your health and preferences.

If you have not seen your GP about erectile dysfunction before, we encourage you to do so. ED can be an early warning sign of heart disease, diabetes, or other health conditions that benefit from early diagnosis and treatment [1]. Your GP can also review your warfarin therapy and overall cardiovascular health, ensuring that any ED treatment fits safely into your broader care plan.

Why choose Cured Pharmacy for ED treatment

Our service is designed to be convenient, confidential, and clinically safe. Every prescription is reviewed by a UK-registered prescriber, and our pharmacy team is available to answer questions about your treatment. We understand that discussing ED can feel awkward, and our online consultation allows you to seek help in private, with the same clinical standards you would expect from a face-to-face appointment.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 5 November 2026]
2. National Institute for Health and Care Excellence. (n.d.). Erectile dysfunction. Clinical Knowledge Summaries. https://cks.nice.org.uk/topics/erectile-dysfunction/ [accessed 5 November 2026]
3. Joint Formulary Committee. (n.d.). Vardenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/vardenafil/ [accessed 5 November 2026]

Information on this page is for educational purposes only and is not medical advice. Prescription treatments require clinical assessment by a UK-registered prescriber. Always consult a qualified healthcare professional before starting or changing any medication.

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