Tadalafil and Amiodarone: Can They Be Taken Together?

Tadalafil and Amiodarone: What You Need to Know About This Interaction

Published: 18 October 2026

Many men taking amiodarone for heart rhythm problems wonder whether tadalafil and amiodarone can be taken together safely. The good news is that tadalafil is not absolutely contraindicated with amiodarone, but the combination does require careful prescriber assessment because both medicines can affect your heart rhythm and blood pressure. This page explains how the interaction works, what your doctor or pharmacist will check, and how to use tadalafil safely if you're on amiodarone.

What is tadalafil and what is amiodarone?

Tadalafil is a prescription medicine used 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 more blood to flow in when you are sexually aroused [3][4]. Tadalafil is the active ingredient in Cialis and is available in on-demand doses (10mg or 20mg taken at least 30 minutes before sex, with effects lasting up to 36 hours) or as a daily low dose (2.5mg or 5mg) [4].

Amiodarone is a prescription medicine used to treat serious irregular heart rhythms (arrhythmias), such as atrial fibrillation or ventricular tachycardia [12]. It works by slowing down electrical signals in the heart to help restore a normal rhythm. Amiodarone is usually prescribed when other treatments have not worked or are unsuitable, and it requires regular monitoring because it can affect the heart, thyroid, liver, lungs and eyes [12].

Because amiodarone affects the heart and tadalafil can lower blood pressure slightly, your prescriber needs to check that your heart is healthy enough for sexual activity and that the combination is safe for you personally [2][4].

How do tadalafil and amiodarone interact?

Tadalafil and amiodarone interact in two main ways. First, both medicines can affect the electrical activity of your heart. Amiodarone is known to prolong the QT interval (a measure of the heart's electrical cycle), and tadalafil may also have a small effect on the QT interval in some people [4][12]. When taken together, there is a theoretical risk that this effect could be additive, although serious heart rhythm problems from this combination are rare.

Second, tadalafil can cause a mild drop in blood pressure, and amiodarone can sometimes lower blood pressure too [4][12]. When combined, this may increase the chance of dizziness, light-headedness or fainting, especially when you stand up quickly. This is usually manageable, but it is important that your prescriber knows you are taking amiodarone so they can assess your overall cardiovascular health and decide whether tadalafil is suitable.

It is also worth noting that amiodarone is a moderate inhibitor of an enzyme called CYP3A4, which breaks down tadalafil in the body [12]. This means amiodarone can slightly increase the levels of tadalafil in your bloodstream, potentially making side effects more likely. For this reason, your prescriber may recommend starting with a lower dose of tadalafil and monitoring how you respond [4].

Is the combination safe?

Tadalafil is not absolutely contraindicated with amiodarone, unlike medicines such as nitrates, nicorandil or riociguat (which must never be taken with tadalafil). However, the combination does require careful assessment by a prescriber who will review your full medical history, current heart function, and all other medicines you are taking [2][4]. If your heart condition is stable and your prescriber judges that sexual activity is safe for you, tadalafil can often be used with appropriate precautions.

What will my prescriber check before prescribing tadalafil with amiodarone?

Before prescribing tadalafil to someone taking amiodarone, your doctor or pharmacist prescriber will carry out a thorough assessment. They will ask about your heart condition, why you are taking amiodarone, and whether your heart rhythm is currently stable. They will also want to know if you have had any recent heart problems, such as a heart attack, stroke, unstable angina or severe heart failure, because tadalafil is not suitable when sexual activity itself is inadvisable [2][4].

Your prescriber will review your blood pressure and check whether you are taking any other medicines that could interact with tadalafil, such as alpha-blockers (e.g. doxazosin, tamsulosin), other blood pressure medicines, or potent CYP3A4 inhibitors [3][4]. They will also ask about any history of prolonged QT interval, fainting episodes, or other heart rhythm abnormalities. If you have had recent blood tests or heart monitoring (such as an ECG), it can be helpful to mention the results.

Based on this information, your prescriber will decide whether tadalafil is safe for you and, if so, which dose to start with. They may recommend beginning with a lower dose (such as 10mg on-demand or 2.5mg daily) and reviewing how you get on [4]. It is essential to be completely honest during your consultation and to declare all medicines, supplements and health conditions, even if you think they are unrelated.

Practical advice for taking tadalafil if you are on amiodarone

If your prescriber approves tadalafil, there are some practical steps you can take to use it safely alongside amiodarone. First, start with the lowest effective dose and do not take more than prescribed. For on-demand tadalafil, take it at least 30 minutes before sexual activity and do not use it more than once a day [4]. If you are prescribed daily tadalafil, take it at the same time each day, with or without food.

Be aware of how you feel when you first start tadalafil. Common side effects include headache, indigestion, back pain and flushing, which usually settle as your body adjusts [4]. However, if you experience dizziness, light-headedness or a rapid or irregular heartbeat, sit or lie down and contact your doctor or pharmacist for advice. Avoid standing up too quickly, especially after lying down, as this can make dizziness worse.

Do not drink large amounts of alcohol when taking tadalafil, as alcohol can lower blood pressure further and make erectile dysfunction worse [4]. Grapefruit juice can increase tadalafil levels in your blood, so it is best to avoid it or limit your intake. Never take tadalafil with nitrates, nicorandil, riociguat, poppers or another PDE5 inhibitor, as these combinations can cause a dangerous drop in blood pressure [3][4].

Keep all your follow-up appointments with your cardiologist or GP, and let them know you are using tadalafil. If your amiodarone dose changes or you start any new medicines, check with your prescriber or pharmacist whether your tadalafil dose needs adjusting. Always carry an up-to-date list of all your medicines, including tadalafil, in case you need emergency treatment.

When to seek urgent help

Seek immediate medical help (call 999 or go to A&E) if you experience chest pain or discomfort during or after sex, as this could be a sign of a heart problem [4]. Also seek urgent help if you have an erection lasting more than four hours (priapism), sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing [3][4]. If you feel very dizzy, faint, or notice a very fast or very slow heartbeat, contact your doctor or NHS 111 straight away.

Are there alternative ED treatments if tadalafil and amiodarone are not suitable together?

If your prescriber decides that tadalafil is not the best option for you while you are taking amiodarone, there are other licensed ED treatments available. Sildenafil (the active ingredient in Viagra) is another PDE5 inhibitor that works in a similar way to tadalafil but has a shorter duration of action (about four to six hours) [3]. Like tadalafil, sildenafil requires the same cardiovascular checks and can interact with amiodarone in similar ways, so your prescriber will assess whether it is suitable.

Other PDE5 inhibitors include vardenafil (Levitra) and avanafil (Spedra), which also need careful assessment if you are on amiodarone [5][6]. Vardenafil in particular is contraindicated with some potent CYP3A4 inhibitors and requires caution with medicines that prolong the QT interval [5]. Your prescriber will choose the most appropriate option based on your individual circumstances.

If PDE5 inhibitors are not suitable, your doctor may discuss non-tablet treatments such as Vitaros (alprostadil cream applied to the tip of the penis) or Caverject (alprostadil injection into the penis) [7]. Vacuum erection devices and psychological therapies such as cognitive behavioural therapy or psychosexual counselling can also help, especially if anxiety or relationship issues are contributing to ED [2]. Your GP or a specialist can refer you to appropriate services.

How Cured Pharmacy can help with tadalafil and amiodarone

Cured Pharmacy is a GPhC-registered online pharmacy (GPhC 9012511) offering discreet, convenient access to ED treatments after a clinical consultation with a UK-registered prescriber. When you request tadalafil through Cured Pharmacy, you will complete a detailed online health questionnaire that asks about all your current medicines, including amiodarone, and any heart conditions or other health problems.

A UK prescriber will review your answers carefully and check whether tadalafil is safe and suitable for you. If you are taking amiodarone, the prescriber will pay particular attention to your cardiovascular health and may ask follow-up questions or request information from your GP if needed. If tadalafil is approved, it will be dispensed by a UK pharmacist and delivered discreetly to your door. If tadalafil is not suitable, the prescriber may suggest an alternative treatment or advise you to see your GP for further assessment [2].

Cured Pharmacy stocks a range of tadalafil products, including generic tadalafil, branded Cialis, and Teva and Avarante brands, in various strengths to suit different needs. All treatments are genuine, UK-licensed medicines. Remember, you should never buy tadalafil from unregulated websites, as counterfeit or unlicensed products can be dangerous and may contain harmful ingredients. Always use a registered pharmacy and declare all your medicines and health conditions during the consultation.

Why see your GP about new ED

If you are experiencing erectile dysfunction for the first time, it is important to see your GP for a full assessment, even if you are already under a cardiologist for your amiodarone treatment [1][2]. ED can be an early warning sign of underlying health problems such as heart disease, diabetes, high blood pressure or high cholesterol, and treating these conditions can improve both your general health and your erections [1][10]. Your GP can arrange blood tests, check your cardiovascular risk, and refer you to a specialist if needed.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 18 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 18 October 2026]
3. Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 18 October 2026]
4. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 18 October 2026]
5. 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 18 October 2026]
6. Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 18 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.