Vardenafil and Naltrexone: Can You Take Them Together?

Vardenafil and Naltrexone: Understanding the Interaction

Published: 2 November 2026

If you're considering vardenafil and naltrexone together, you'll be reassured to know that no major interaction between these two medicines is commonly reported in clinical practice. Vardenafil is a prescription treatment for erectile dysfunction (ED), while naltrexone is used to help manage alcohol dependence and opioid addiction. Because they work through completely different mechanisms in the body, they do not typically interfere with each other's effectiveness or safety. However, every medicine you take—prescription, over-the-counter, or herbal—must be declared during your consultation, so your prescriber or pharmacist can check your full medication list and medical history before approving treatment.

What Is Vardenafil and How Does It Work?

Vardenafil (the generic version of Levitra) is a prescription medicine licensed in the UK to treat erectile dysfunction in adult men [5]. It belongs to a group of medicines called phosphodiesterase type 5 (PDE5) inhibitors, which also includes sildenafil (Viagra), tadalafil (Cialis), and avanafil (Spedra) [1][2].

Vardenafil works by relaxing the blood vessels in the penis, allowing more blood to flow into the area when you are sexually aroused [5]. This helps you achieve and maintain an erection suitable for sexual activity. It is important to understand that vardenafil does not work automatically—sexual stimulation is needed for the medicine to be effective [5].

Vardenafil is typically taken about 25 to 60 minutes before sexual activity, and the effect can last for several hours [5]. The usual starting dose is 10 mg, which can be adjusted by your prescriber depending on how well it works and whether you experience any side effects. The maximum recommended dose is 20 mg, and you should not take more than one dose in a 24-hour period [5]. Vardenafil is only available on prescription in the UK, following a clinical assessment by a registered prescriber.

What Is Naltrexone and What Is It Used For?

Naltrexone is a prescription medicine used primarily to help people who have stopped drinking alcohol or using opioids to remain abstinent. It works by blocking opioid receptors in the brain, which reduces cravings and the rewarding effects of alcohol and opioids. Naltrexone does not treat withdrawal symptoms and is usually started after detoxification is complete.

Naltrexone is available as tablets (typically 50 mg taken once daily) or as a long-acting injection given once a month. It is part of a comprehensive treatment programme that includes counselling and psychosocial support. Because naltrexone acts on the central nervous system and opioid pathways, it does not directly affect blood flow, blood pressure, or the mechanisms involved in achieving an erection.

Common side effects of naltrexone include nausea, headache, dizziness, fatigue, and sleep disturbances. These are usually mild and improve over time. Naltrexone must not be taken if you are currently using opioid painkillers or if you have severe liver disease. Your doctor will check your liver function before and during treatment. It is essential to tell your prescriber about all medicines you are taking, including treatments for erectile dysfunction.

Does Naltrexone Cause Erectile Dysfunction?

Sexual side effects, including reduced libido and erectile difficulties, have been reported by some people taking naltrexone, although they are not common. If you notice new or worsening erectile problems after starting naltrexone, discuss this with your GP or prescriber. It is important not to stop naltrexone suddenly without medical advice, as this could affect your recovery from alcohol or opioid dependence. Your doctor can help you explore whether the ED is related to the medicine, to psychological factors, or to other health conditions.

Vardenafil and Naltrexone: Do They Interact?

No major interaction between vardenafil and naltrexone is commonly reported in clinical practice or listed in standard UK prescribing references. This is because the two medicines work through entirely different mechanisms and are processed by different pathways in the body. Vardenafil acts on blood vessels in the penis by inhibiting the PDE5 enzyme, while naltrexone blocks opioid receptors in the brain and does not significantly affect blood pressure or vascular function.

However, it is still essential to declare that you are taking naltrexone (or any other medicine) when you request vardenafil. During the online consultation at Cured Pharmacy, a UK-registered prescriber will review your full medical history and current medications to ensure vardenafil is safe and appropriate for you. This check is a legal and clinical requirement for all prescription medicines.

While the combination is not expected to cause problems, individual responses can vary. If you experience any unusual symptoms—such as dizziness, fainting, chest pain, or changes in your erection quality—after starting vardenafil while on naltrexone, contact your GP or pharmacist promptly. Never stop or change a prescribed medicine without professional advice, as this could affect your overall treatment plan.

What Your Prescriber Checks Before Approving Vardenafil

Before vardenafil can be prescribed, a UK-registered prescriber must assess whether it is safe and suitable for you [2][5]. This assessment includes reviewing your current medicines, medical conditions, and lifestyle factors. The prescriber will specifically check for any contraindications—conditions or medicines that make vardenafil unsafe.

Vardenafil must never be taken with nitrates (such as GTN spray, isosorbide mononitrate, or isosorbide dinitrate), nicorandil, riociguat, or recreational drugs known as 'poppers' (amyl or alkyl nitrites) [5]. Combining vardenafil with any of these can cause a dangerous drop in blood pressure. You must also not take vardenafil alongside another PDE5 inhibitor, such as sildenafil, tadalafil, or avanafil.

Other important checks include whether you take alpha-blockers for prostate symptoms or high blood pressure (such as doxazosin or tamsulosin), as these can add to the blood-pressure-lowering effect of vardenafil and cause dizziness [5]. If you are on an alpha-blocker, your prescriber will usually start you on the lowest dose of vardenafil and ensure you are stable on the alpha-blocker first. Medicines that affect how vardenafil is broken down in the liver—such as certain antifungals, antibiotics, or HIV treatments—may also require dose adjustments or make vardenafil unsuitable [5].

Medical Conditions That Affect Vardenafil Safety

Vardenafil is not suitable if sexual activity itself is inadvisable—for example, if you have had a recent heart attack or stroke, unstable angina, severe heart failure, or very low blood pressure [5]. It is also contraindicated if you have a history of non-arteritic anterior ischaemic optic neuropathy (NAION), a rare condition causing sudden vision loss, or certain inherited retinal disorders [5]. Your prescriber will ask about these conditions during the consultation to ensure vardenafil is safe for you.

Practical Advice for Taking Vardenafil Safely with Naltrexone

If your prescriber approves vardenafil while you are taking naltrexone, follow the dosing instructions carefully. Take vardenafil about 25 to 60 minutes before you plan to have sex, and do not take more than one dose in 24 hours [5]. Swallow the tablet whole with water; it can be taken with or without food, although a heavy, high-fat meal may delay how quickly it works.

Avoid drinking large amounts of alcohol when using vardenafil, as alcohol can worsen erectile dysfunction and increase the risk of side effects such as dizziness and low blood pressure [5]. Grapefruit juice can raise vardenafil levels in the blood and should be avoided. If you feel dizzy or light-headed after taking vardenafil, sit or lie down until the feeling passes, and avoid driving or operating machinery.

Keep all your medicines in their original packaging, stored safely away from children. Do not share vardenafil with anyone else, even if they have similar symptoms. If you experience any side effects that concern you, or if vardenafil does not work as expected, speak to your prescriber or pharmacist. They can adjust your dose or suggest an alternative treatment. Remember, vardenafil only works when you are sexually aroused—it is not an aphrodisiac and will not increase sexual desire.

When to Seek Urgent Medical Help

Although serious side effects from vardenafil are uncommon, you should know the warning signs that require immediate medical attention. If you develop an erection that lasts longer than four hours (priapism), go to A&E or call 999 straight away [5]. Priapism is a medical emergency that can cause permanent damage to the penis if not treated promptly.

Seek urgent help if you experience sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing, which may be accompanied by ringing in the ears or dizziness [5]. These are rare but serious side effects. If you develop chest pain during or after sexual activity, stop and seek medical advice immediately—do not take nitrate medicines for chest pain if you have used vardenafil within the last 24 hours, as this combination is dangerous [5].

Allergic reactions to vardenafil are rare but can include swelling of the face, lips, tongue, or throat, severe skin rash, or difficulty breathing. If you experience any of these symptoms, call 999 or go to A&E. Always carry a list of your current medicines, including vardenafil and naltrexone, so healthcare professionals can provide safe and appropriate treatment in an emergency.

Reporting Side Effects

If you experience any side effects from vardenafil, whether listed in the patient information leaflet or not, you can report them via the UK Yellow Card Scheme at yellowcard.mhra.gov.uk or by searching for 'Yellow Card' in the Google Play or Apple App Store. Reporting side effects helps improve the safety information available for all patients.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 2 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 2 November 2026]
3. Joint Formulary Committee. (n.d.). Vardenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/vardenafil/ [accessed 2 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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