Vardenafil and Disulfiram: Can They Be Taken Together?

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Key takeaways

• No major direct interaction between vardenafil and disulfiram is commonly reported in UK guidance
• Both medicines can affect blood pressure; your prescriber will assess your overall health
• You must avoid all alcohol if taking disulfiram, as it worsens ED and causes severe reactions
• Always declare both medicines during your online consultation for a full safety review
• Vardenafil is only supplied after assessment by a UK-registered prescriber

What is vardenafil and how does it work?

Vardenafil (also known by the brand name Levitra) is a prescription medicine used to treat erectile dysfunction in men. 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 does not cause an erection on its own—sexual stimulation is still needed.

In the UK, vardenafil is available in 5 mg, 10 mg, and 20 mg tablets. The usual starting dose is 10 mg, taken about 25 to 60 minutes before sexual activity, and it should not be used more than once a day [5]. The effect can last for several hours, but this varies between individuals. Vardenafil is only available on prescription after a clinical assessment by a UK-registered prescriber, who will check your medical history, current medicines, and whether the treatment is suitable and safe for you.

What is disulfiram and why is it prescribed?

Disulfiram (commonly known by the brand name Antabuse) is a prescription medicine used to help people maintain abstinence from alcohol. It works by blocking an enzyme called aldehyde dehydrogenase, which is involved in breaking down alcohol in the body. If someone taking disulfiram drinks alcohol, even a small amount, they experience very unpleasant symptoms—including flushing, nausea, vomiting, headache, rapid heartbeat, and a drop in blood pressure. This reaction is designed to deter alcohol consumption.

Disulfiram is prescribed as part of a supervised treatment programme for alcohol dependence. It requires commitment to complete abstinence from alcohol, including avoiding alcohol in foods, mouthwashes, and medicines. Because disulfiram can cause significant reactions and affect how the body processes other substances, your prescriber will review all your current medicines and health conditions before starting treatment.

How disulfiram affects your body

Disulfiram does not just block alcohol metabolism—it can also affect liver enzymes that break down other medicines. This means it has the potential to interact with a wide range of drugs. The medicine can also lower blood pressure in some people, particularly during a disulfiram-alcohol reaction. Anyone taking disulfiram must be monitored regularly by their healthcare team to check liver function and ensure the treatment remains safe and effective.

At a glance

Vardenafil and disulfiram: is there an interaction?

No major direct interaction between vardenafil and disulfiram is commonly reported in UK prescribing resources such as the British National Formulary [5]. This means that, based on current evidence, the two medicines do not have a well-documented mechanism that would make them unsafe to use together in most people. However, this does not mean the combination is automatically suitable for everyone.

Both medicines can affect blood pressure. Vardenafil can cause a mild drop in blood pressure, particularly when combined with other medicines that lower blood pressure or in people who drink alcohol [5]. Disulfiram can also lower blood pressure, especially during a reaction with alcohol. If you are taking both medicines, your prescriber will need to assess your overall cardiovascular health, blood pressure, and any other medicines you are taking to ensure the combination is safe for you.

It is essential that you declare both medicines during your online consultation. Your prescriber will review your full medication list, medical history, and current health to decide whether vardenafil is appropriate. Never assume a combination is safe without professional advice, and do not stop or change a prescribed medicine like disulfiram without consulting your doctor or pharmacist.

What will my prescriber check before approving vardenafil?

When you request vardenafil through an online consultation at Cured Pharmacy, a UK-registered prescriber will review your answers to ensure the treatment is safe and suitable. They will check whether you have any conditions that make vardenafil unsuitable, such as recent heart attack or stroke, unstable angina, severe heart failure, very low blood pressure, or a history of sudden vision loss (non-arteritic anterior ischaemic optic neuropathy, or NAION) [5][12].

Your prescriber will also review all your current medicines. Vardenafil must never be taken with nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, or recreational drugs called 'poppers' (amyl or alkyl nitrites), because the combination can cause a dangerous drop in blood pressure [5]. If you are taking disulfiram, the prescriber will note this and assess whether your blood pressure, liver function, and overall health make vardenafil a safe choice.

If you are also taking medicines such as alpha-blockers (for prostate or blood pressure), potent CYP3A4 inhibitors (such as ritonavir, ketoconazole, or clarithromycin), or other blood-pressure-lowering drugs, your prescriber may adjust the dose of vardenafil or advise against it. Vardenafil is contraindicated or requires dose adjustment with potent CYP3A4 inhibitors [5][12]. Always provide complete and accurate information during your consultation.

Why alcohol abstinence matters with disulfiram

If you are taking disulfiram, you must avoid all alcohol. This is critical not only to prevent the disulfiram-alcohol reaction but also because heavy alcohol use can worsen erectile dysfunction and reduce the effectiveness of vardenafil [1]. Alcohol can also add to the blood-pressure-lowering effects of vardenafil, increasing the risk of dizziness or fainting. Your prescriber will expect you to be committed to alcohol abstinence if you are on disulfiram, and this will be part of the safety assessment.

Practical advice for taking vardenafil and disulfiram safely

If your prescriber approves vardenafil while you are taking disulfiram, follow these practical steps to use both medicines safely. Take vardenafil exactly as prescribed—usually 10 mg about 25 to 60 minutes before sexual activity, and no more than once a day [5]. Swallow the tablet whole with water. Do not take vardenafil with grapefruit juice, as this can raise the level of the medicine in your blood and increase the risk of side effects.

Continue taking disulfiram as directed by your doctor, and maintain complete abstinence from alcohol in all forms, including in food, medicines, and toiletries. If you experience dizziness, light-headedness, or a drop in blood pressure after taking vardenafil, sit or lie down until you feel better, and avoid driving or operating machinery. If symptoms are severe or do not improve, contact your GP or NHS 111 for advice.

Do not take vardenafil if you have consumed alcohol, even if you are not currently taking disulfiram. If you stop taking disulfiram, remember that it can remain in your system for up to two weeks, and you must continue to avoid alcohol during this time. Always inform any healthcare professional you see—GP, pharmacist, or hospital doctor—that you are taking both vardenafil and disulfiram, so they can check for any additional interactions with new medicines.

When to seek urgent help and other ED treatment options

Seek urgent medical help if you experience an erection lasting more than four hours (priapism), sudden loss of vision or hearing, or chest pain during sexual activity while taking vardenafil [5][12]. These are rare but serious side effects that require immediate attention. Call 999 or go to A&E. If you have a severe disulfiram-alcohol reaction (such as difficulty breathing, chest pain, or collapse), this is also a medical emergency.

If vardenafil is not suitable for you, or if you prefer an alternative, other PDE5 inhibitors are available on prescription after an online consultation. Sildenafil (generic Viagra) is taken about one hour before sex and is available from £0.45 per tablet (first order with code Ednew: £0.36). Tadalafil (generic Cialis) can be taken on-demand or daily; on-demand tadalafil starts at £7.95 (first order with code Ednew: £6.36) and can last up to 36 hours [4]. Avanafil (Spedra) works in as little as 15 to 30 minutes and is priced at £20.95 (first order with code Ednew: £16.76) [6].

All PDE5 inhibitors work in a similar way and have similar interactions and precautions. Your prescriber will help you choose the most suitable option based on your health, preferences, and other medicines. If oral treatments are not appropriate, other options such as Vitaros (alprostadil cream) or Caverject (alprostadil injection) may be considered [7]. Always see your GP if you have new or worsening erectile dysfunction, as it can be an early sign of heart disease or diabetes [1][2].

How Cured Pharmacy can help

Cured Pharmacy is a GPhC-registered online pharmacy (GPhC 9012511) offering discreet, convenient access to ED treatments after a clinical consultation reviewed by a UK-registered prescriber. You complete a short online questionnaire, and a prescriber checks your answers, medical history, and current medicines to ensure the treatment is safe. If approved, your medicine is dispensed by our pharmacy and delivered discreetly to your door. You can ask questions at any stage, and our pharmacy team is here to support you.

When to get urgent help

• Erection lasting more than 4 hours (priapism)—call 999 or go to A&E immediately
• Sudden loss of vision or hearing—stop vardenafil and seek urgent medical help
• Chest pain during sexual activity—stop and call 999
• Severe disulfiram-alcohol reaction (difficulty breathing, chest pain, collapse)—call 999
• Severe dizziness, fainting, or very low blood pressure—seek same-day medical advice

Call 999 or go to A&E in an emergency, or contact NHS 111 for urgent advice.