Vardenafil and Entacapone: Can They Be Taken Together?

Vardenafil and Entacapone: Understanding the Interaction

Published: 30 October 2026

If you've been prescribed vardenafil and entacapone, you may be wondering whether these two medicines can be taken together safely. Vardenafil is a PDE5 inhibitor used to treat erectile dysfunction, while entacapone is a COMT inhibitor used alongside levodopa to manage Parkinson's disease. No major direct interaction between vardenafil and entacapone is commonly reported in clinical references, but both medicines can affect blood pressure, so your prescriber will carefully review your full medical history and current medications during your consultation to ensure the combination is appropriate for you.

What Is Vardenafil and How Does It Work?

Vardenafil is a prescription medicine licensed in the UK to treat erectile dysfunction (ED). 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 [5]. Vardenafil is the generic version of Levitra and is available in 5mg, 10mg, and 20mg tablets.

You typically take vardenafil about 25 to 60 minutes before sexual activity, and it works only when you are sexually stimulated [5]. The effects can last for several hours, but you should not take more than one dose in 24 hours. Common side effects include headache, flushing, nasal congestion, and indigestion. Vardenafil is not suitable for everyone, particularly if you have severe heart problems, very low blood pressure, or if you take certain other medicines such as nitrates.

What Is Entacapone and Why Is It Prescribed?

Entacapone is a prescription medicine used to treat Parkinson's disease. It is a COMT (catechol-O-methyltransferase) inhibitor that works by blocking an enzyme that breaks down levodopa, a key medicine for Parkinson's symptoms. By slowing the breakdown of levodopa, entacapone helps maintain more stable levels of the medicine in your bloodstream, which can improve motor symptoms and reduce 'off' periods when Parkinson's symptoms return.

Entacapone is always taken alongside levodopa and a dopa-decarboxylase inhibitor (such as carbidopa or benserazide). It does not work on its own. Common side effects include diarrhoea, nausea, urine discolouration (reddish-brown), and increased involuntary movements. Entacapone can also cause dizziness or low blood pressure, particularly when standing up, which is important when considering other medicines that affect blood pressure.

How Entacapone Affects Blood Pressure

One of the known effects of entacapone, particularly when used with levodopa, is the potential to cause orthostatic hypotension—a sudden drop in blood pressure when you stand up. This can lead to dizziness, light-headedness, or even fainting. Because vardenafil can also lower blood pressure slightly as part of its mechanism, your prescriber will want to ensure that the combination does not increase your risk of symptomatic low blood pressure or falls.

Do Vardenafil and Entacapone Interact?

There is no well-documented direct pharmacological interaction between vardenafil and entacapone in the major UK clinical references [5][12]. Entacapone does not significantly affect the liver enzymes (CYP3A4) that break down vardenafil, and vardenafil does not interfere with the way entacapone works on COMT. However, both medicines can influence blood pressure, which means there is a theoretical risk of additive blood-pressure-lowering effects.

Your prescriber will assess whether the combination is safe for you by reviewing your current blood pressure control, any history of dizziness or fainting, your overall cardiovascular health, and all other medicines you take. If you are stable on entacapone and your blood pressure is well managed, vardenafil may still be an option, often starting at the lowest effective dose. It is essential that you declare all your current medicines, including those for Parkinson's disease, during your online consultation so the prescriber can make an informed decision.

What Your Prescriber Will Check Before Approving Vardenafil and Entacapone Together

During your consultation at Cured Pharmacy, the UK-registered prescriber will review several important factors. They will ask about your current dose of entacapone and levodopa, how well your Parkinson's symptoms are controlled, and whether you experience dizziness, fainting, or low blood pressure when standing. They will also check your cardiovascular health, including any history of heart disease, stroke, or angina, because sexual activity itself places demands on the heart.

The prescriber will ensure you are not taking any medicines that are absolutely contraindicated with vardenafil, such as nitrates (GTN spray, isosorbide mononitrate), nicorandil, riociguat, or recreational drugs known as 'poppers' [5]. If you take other blood-pressure medicines, alpha-blockers, or medicines that affect liver enzymes, these will also be reviewed. If the prescriber judges that the combination of vardenafil and entacapone is appropriate for you, they may recommend starting with the lowest dose of vardenafil (5mg) and monitoring how you respond.

Why Starting with a Lower Dose Matters

Starting with a lower dose of vardenafil (such as 5mg) allows you and your prescriber to see how your body responds to the medicine while minimising the risk of side effects, particularly dizziness or low blood pressure. If the lower dose is well tolerated and effective, it can be continued. If it does not provide sufficient benefit, the dose may be increased under medical supervision. Never adjust your dose or take more than prescribed without consulting your prescriber.

Practical Advice for Taking Vardenafil and Entacapone Safely

If your prescriber approves vardenafil for you while you are taking entacapone, there are several practical steps you can take to use both medicines safely. Take vardenafil exactly as prescribed, usually about 25 to 60 minutes before sexual activity, and do not take more than one dose in 24 hours [5]. Continue taking your entacapone and levodopa exactly as directed by your Parkinson's specialist—do not stop or change the dose without medical advice.

Be cautious when standing up, particularly after taking vardenafil, as both medicines can contribute to dizziness. Sit on the edge of the bed for a moment before standing, and rise slowly. Avoid heavy alcohol, as it can worsen erectile dysfunction, increase the risk of low blood pressure, and interact with your Parkinson's medicines. If you experience dizziness, light-headedness, or fainting after taking vardenafil, do not drive or operate machinery, and contact your GP or prescriber for advice. Keep all your healthcare professionals informed about every medicine you take, including over-the-counter products and supplements.

When to Seek Urgent Medical Help with Vardenafil and Entacapone

While serious side effects are uncommon, you should know the warning signs that require urgent medical attention. If you develop an erection that lasts longer than four hours (priapism), go to A&E immediately, as this can cause permanent damage if not treated promptly [5]. Sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing (sometimes with ringing in the ears or dizziness), requires urgent medical assessment.

If you experience chest pain during or after sexual activity, stop and seek medical help—do not take nitrate medicines such as GTN spray, as the combination with vardenafil can cause a dangerous drop in blood pressure [5]. Severe dizziness, fainting, or a very fast or irregular heartbeat should also prompt you to contact 111 or your GP urgently. If you notice any new or worsening symptoms after starting vardenafil while on entacapone, speak to your prescriber or pharmacist as soon as possible.

Reporting Side Effects

If you experience any side effect that concerns you, whether listed in the patient information leaflet or not, you can report it via the Yellow Card Scheme at yellowcard.mhra.gov.uk or by searching for 'Yellow Card' in the Google Play or Apple App Store. Reporting helps improve the safety information available for all patients. You can also discuss any concerns with the pharmacist team at Cured Pharmacy.

Scientific References

1. Joint Formulary Committee. (n.d.). Vardenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/vardenafil/ [accessed 30 October 2026]
2. Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 30 October 2026]
3. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 30 October 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.