Tadalafil and Disulfiram: Can They Be Taken Together?

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Tadalafil and Disulfiram: Understanding the Interaction

Published: 20 October 2026

If you're prescribed disulfiram for alcohol dependence and considering tadalafil for erectile dysfunction, you may wonder whether tadalafil and disulfiram can be taken together safely. The good news is that no major direct interaction between these two medicines is commonly reported in clinical literature [3][4]. However, both medicines can affect your cardiovascular system in different ways, so your prescriber will need to review your full medical history and current health status before approving tadalafil treatment.

What is tadalafil and how does it work?

Tadalafil is a prescription medicine used to treat erectile dysfunction (ED) in men [4]. 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're sexually aroused [1]. Unlike some other ED treatments, tadalafil has a long duration of action—its effects can last up to 36 hours, which is why it's sometimes called 'the weekend pill' [4].

Tadalafil is available in two forms: on-demand tablets (usually 10mg or 20mg taken at least 30 minutes before sexual activity) and daily low-dose tablets (2.5mg or 5mg taken once a day) [4]. The medicine only works when you're sexually stimulated; it won't cause an erection on its own. Tadalafil is the active ingredient in branded Cialis as well as several generic versions, all of which work in the same way [4].

What is disulfiram and why is it prescribed?

Disulfiram (commonly known by the brand name Antabuse) is a prescription medicine used to support people recovering from alcohol dependence [12]. It works by blocking an enzyme called aldehyde dehydrogenase, which is involved in breaking down alcohol in the body. When someone taking disulfiram drinks alcohol, even a small amount, they experience very unpleasant reactions including flushing, nausea, vomiting, headache, rapid heartbeat, and a drop in blood pressure [12].

This 'deterrent effect' helps people maintain abstinence from alcohol as part of a broader treatment programme. Disulfiram is usually prescribed alongside counselling and support services. The medicine stays active in your system for up to two weeks after you stop taking it, so the reaction to alcohol can occur even days after your last dose [12]. Because disulfiram can affect heart rate and blood pressure when combined with alcohol, prescribers carefully assess cardiovascular health before starting treatment.

How do tadalafil and disulfiram interact?

There is no well-documented direct pharmacological interaction between tadalafil and disulfiram—they work through completely different mechanisms and are not known to interfere with each other's breakdown or effectiveness [3][4]. Tadalafil is primarily metabolised by liver enzymes (mainly CYP3A4), while disulfiram works by inhibiting aldehyde dehydrogenase. Neither medicine is listed as a contraindication or significant interaction for the other in UK prescribing guidance [3][4].

However, both medicines can affect your cardiovascular system, which is why your prescriber needs to review the combination carefully. Tadalafil can cause a small drop in blood pressure, particularly when you first start taking it [4]. Disulfiram, when combined with alcohol, causes significant cardiovascular effects including low blood pressure and rapid heartbeat [12]. If you're taking disulfiram, you should be completely abstinent from alcohol, which actually removes one concern—alcohol itself can worsen erectile dysfunction and adds to the blood-pressure-lowering effect of tadalafil [1][4].

Why cardiovascular health matters

Your prescriber will pay particular attention to your heart and blood pressure when considering tadalafil alongside disulfiram. Sexual activity itself places demands on your heart, and tadalafil is not suitable if sexual activity is inadvisable—for example, if you've had a recent heart attack or stroke, have unstable angina, or severe heart failure [4]. The prescriber will check your blood pressure, review any heart conditions, and ensure you're not taking medicines that are contraindicated with tadalafil, such as nitrates (GTN spray, isosorbide mononitrate), nicorandil, riociguat, or recreational drugs called 'poppers' [3][4]. These combinations can cause a dangerous drop in blood pressure and must never be taken together.

What your prescriber checks before approving tadalafil and disulfiram together

When you request tadalafil through Cured Pharmacy's online consultation, a UK-registered prescriber reviews your medical history, current medicines, and overall health. If you're taking disulfiram, the prescriber will specifically check your cardiovascular health, blood pressure readings, and whether you have any heart conditions that might make tadalafil unsuitable [2][4]. They'll confirm you're not taking any medicines that are contraindicated with tadalafil, such as nitrates, nicorandil, riociguat, or another PDE5 inhibitor [3][4].

The prescriber will also review why you're taking disulfiram and confirm you're abstinent from alcohol, as heavy alcohol use can worsen erectile dysfunction and is not recommended with tadalafil [1][4]. If you're on other blood-pressure medicines or alpha-blockers (such as doxazosin or tamsulosin), the prescriber will ensure you're stable on those treatments and may recommend starting tadalafil at a lower dose to minimise the risk of dizziness or low blood pressure [3][4]. This thorough review ensures tadalafil is safe and appropriate for you.

Starting tadalafil safely

If your prescriber approves tadalafil, they'll usually recommend starting with the lowest effective dose—often 10mg for on-demand use or 2.5mg if you're considering daily treatment [4]. You'll be advised to take the medicine as directed, avoid grapefruit juice (which can raise tadalafil levels), and watch for any side effects such as headache, indigestion, back pain, or dizziness [4]. If you experience chest pain during sexual activity, sudden loss of vision or hearing, or an erection lasting more than four hours, you must seek urgent medical help [4]. Your prescriber may suggest a follow-up to review how the treatment is working and whether any dose adjustment is needed.

Practical advice for taking tadalafil and disulfiram

If you're approved for both medicines, take each exactly as prescribed. Disulfiram is usually taken once daily, and you must avoid all sources of alcohol—including in food, mouthwash, and some medicines—while taking it and for up to two weeks after stopping [12]. Tadalafil on-demand tablets (10mg or 20mg) should be taken at least 30 minutes before sexual activity, with effects lasting up to 36 hours; daily tadalafil (2.5mg or 5mg) is taken once a day at roughly the same time [4]. Do not take more than one dose of on-demand tadalafil in 24 hours [4].

Keep both medicines in their original packaging, away from heat and moisture, and out of reach of children. If you develop any new symptoms—particularly dizziness, fainting, chest discomfort, or visual changes—contact your GP or pharmacist promptly. Never share your medicines with others, and do not stop or change your disulfiram without discussing it with the doctor who prescribed it, as stopping suddenly can affect your alcohol-dependence treatment plan. If you have any questions about timing, side effects, or how the medicines work together, the pharmacist team at Cured Pharmacy is available to help.

Other ED treatment options at Cured Pharmacy

Tadalafil is one of several effective prescription treatments for erectile dysfunction available through Cured Pharmacy's online service. All require a consultation reviewed by a UK prescriber. Sildenafil (generic Viagra) is a shorter-acting PDE5 inhibitor, usually taken about one hour before sex, with effects lasting around four to six hours [3]. Vardenafil (generic Levitra) works similarly, taken 25–60 minutes before sexual activity [5]. Avanafil (Spedra) is the fastest-acting option, effective in as little as 15–30 minutes [6][11].

All PDE5 inhibitors work in a similar way and have the same contraindications—none can be taken with nitrates, nicorandil, riociguat, poppers, or another PDE5 inhibitor [3][4][5][6]. If tadalafil is not suitable for you, your prescriber may suggest one of these alternatives, depending on your medical history and preferences. The choice often comes down to how quickly you want the medicine to work and how long you want the effect to last. Every prescription is dispensed by our GPhC-registered pharmacy and delivered discreetly to your door, with ongoing support from our pharmacist team.

When to see your GP

If you're experiencing erectile dysfunction for the first time, it's important to see your GP for a full assessment [1][2]. ED can be an early warning sign of underlying health conditions such as heart disease, diabetes, or high blood pressure, all of which benefit from early diagnosis and treatment [1][10]. Your GP can arrange blood tests, check your cardiovascular health, review your medicines, and discuss lifestyle factors that may be contributing to ED, such as smoking, lack of exercise, or stress [2]. Once any underlying causes have been addressed or ruled out, your GP can refer you for ED treatment or you can access it through a registered online pharmacy like Cured Pharmacy, where a prescriber will review your suitability.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 20 October 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 20 October 2026]
3. Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 20 October 2026]
4. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 20 October 2026]
5. Joint Formulary Committee. (n.d.). Vardenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/vardenafil/ [accessed 20 October 2026]
6. Joint Formulary Committee. (n.d.). Avanafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/avanafil/ [accessed 20 October 2026]
7. Feldman, H. A., Goldstein, I., Hatzichristou, D. G., Krane, R. J., & McKinlay, J. B. (1994). Impotence and its medical and psychosocial correlates: Results of the Massachusetts Male Aging Study. Journal of Urology, 151(1), 54–61. https://pubmed.ncbi.nlm.nih.gov/8254833/ [accessed 20 October 2026]
8. National Institute for Health and Care Excellence. (2014). Erectile dysfunction: avanafil (ESNM45). https://www.nice.org.uk/advice/esnm45 [accessed 20 October 2026]
9. Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 20 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.