Tadalafil and Eplerenone: Can They Be Taken Together?

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Tadalafil and Eplerenone: Understanding the Interaction

Published: 20 October 2026

Many men prescribed eplerenone for heart conditions or high blood pressure wonder whether tadalafil and eplerenone can be taken together safely. The good news is that no major direct interaction is commonly reported between these two medicines, but both can lower blood pressure, so careful monitoring and prescriber review are essential. This page explains what each medicine does, how they may interact, what your doctor or pharmacist checks, and practical steps to use them safely.

What Is Tadalafil and How Does It Work?

Tadalafil is a prescription medicine used to treat erectile dysfunction (ED) in men. It belongs to a group of medicines called phosphodiesterase type 5 (PDE5) inhibitors, which work by relaxing blood vessels in the penis, allowing increased blood flow when you are sexually aroused [4]. Tadalafil is the active ingredient in branded Cialis and is also available as a lower-cost generic.

Tadalafil is available in two forms: on-demand tablets (usually 10 mg or 20 mg) taken at least 30 minutes before sexual activity, with effects lasting up to 36 hours, and daily low-dose tablets (2.5 mg or 5 mg) for men who prefer spontaneity [4]. It does not cause an erection on its own—sexual stimulation is still needed. Because tadalafil relaxes blood vessels throughout the body, it can also cause a small drop in blood pressure, which is usually well tolerated but important when combined with other blood-pressure-lowering medicines [4].

What Is Eplerenone and Why Is It Prescribed?

Eplerenone is a prescription medicine known as a potassium-sparing diuretic (water tablet) and selective aldosterone blocker. It is used to treat high blood pressure and to reduce the risk of further heart problems in people who have had a heart attack and have heart failure or reduced heart function. Eplerenone works by blocking the action of aldosterone, a hormone that can cause the body to retain salt and water, leading to increased blood pressure and strain on the heart.

Unlike some other diuretics, eplerenone helps the body get rid of excess fluid and sodium while retaining potassium, which is why it is called potassium-sparing. Common side effects include dizziness (especially when standing up), headache, and changes in potassium levels, which is why regular blood tests are usually recommended. Because eplerenone lowers blood pressure, combining it with other medicines that also reduce blood pressure—including tadalafil—requires careful assessment by your prescriber.

How Eplerenone Affects Blood Pressure

Eplerenone reduces blood pressure by helping your kidneys remove excess salt and water from the body and by blocking aldosterone's effects on blood vessels. This reduction in fluid volume and relaxation of blood vessel walls leads to lower blood pressure overall. When you take another medicine that also lowers blood pressure, such as tadalafil, the combined effect can sometimes cause dizziness, light-headedness, or fainting, particularly when you stand up quickly. This is why your prescriber will review all your current medicines and may adjust doses or give specific advice about timing and monitoring.

Tadalafil and Eplerenone: How Do They Interact?

No major direct pharmacological interaction is commonly reported between tadalafil and eplerenone—they work through different mechanisms and are not known to interfere with each other's metabolism or effectiveness. However, both medicines can lower blood pressure, and when taken together, this blood-pressure-lowering effect may be additive [4]. In plain English, this means the combined effect on your blood pressure may be greater than either medicine alone, which can increase the risk of dizziness, light-headedness, or fainting, especially when you first stand up.

This interaction is usually manageable and does not mean the combination is unsafe for everyone. Many men take tadalafil alongside blood-pressure medicines, including diuretics like eplerenone, without problems. The key is that your prescriber must know about all your current medicines, assess your overall cardiovascular health, and may start you on a lower dose of tadalafil or give you specific advice about timing and monitoring. If you are stable on eplerenone and your blood pressure is well controlled, your doctor or pharmacist can determine whether tadalafil is suitable and what precautions are needed.

What Your Prescriber Checks Before Prescribing Tadalafil with Eplerenone

When you request tadalafil through an online consultation at Cured Pharmacy or see your GP, the prescriber will review your full medical history and current medicines, including eplerenone. They will check your blood pressure control, any history of dizziness or fainting, and whether you have other cardiovascular conditions such as heart failure, angina, or a recent heart attack or stroke [1][2]. If you are taking eplerenone, it suggests you have a heart condition or high blood pressure, so the prescriber will assess whether sexual activity is safe for you and whether tadalafil is appropriate.

The prescriber may recommend starting with a lower dose of tadalafil (for example, 10 mg on-demand rather than 20 mg, or 2.5 mg daily rather than 5 mg) to minimise the risk of low blood pressure [4]. They will also ask about other medicines you take, including any alpha-blockers (such as doxazosin or tamsulosin), nitrates, or other blood-pressure medicines, as these can further increase the risk. You should never take tadalafil with nitrates (GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, or poppers, as this combination can cause a dangerous drop in blood pressure [4]. Your prescriber will give you clear advice tailored to your situation.

Why Your Blood Pressure Matters

Blood pressure is a key factor in deciding whether tadalafil is safe for you. Very low blood pressure (hypotension) can make you feel dizzy, weak, or faint, and tadalafil can make this worse. Conversely, uncontrolled high blood pressure increases the risk of heart attack and stroke, and sexual activity itself places extra demand on your heart [1]. Your prescriber will want to know your recent blood pressure readings and whether you have experienced any symptoms such as dizziness or chest pain. If your blood pressure is well controlled on eplerenone and you have no other high-risk cardiovascular conditions, tadalafil is often suitable, but the decision must be individualised.

Practical Advice for Taking Tadalafil and Eplerenone Together

If your prescriber approves tadalafil while you are taking eplerenone, follow their instructions carefully. Take tadalafil exactly as prescribed—do not take more than the recommended dose or use it more often than once a day (for on-demand tablets) [4]. If you feel dizzy or light-headed, sit or lie down until the feeling passes, and avoid standing up quickly, especially after lying down or sitting for a long time. Avoid heavy alcohol, as it can worsen dizziness and make erectile dysfunction worse [1].

Monitor how you feel, particularly when you first start tadalafil or if your dose is changed. If you experience persistent dizziness, fainting, chest pain during sex, or any other concerning symptoms, stop taking tadalafil and contact your GP or pharmacist promptly. Do not stop taking eplerenone or change its dose without medical advice, as it is treating an important underlying condition. Keep all your medicines up to date in your online consultation or GP records, and let your prescriber know if any new medicines are started or stopped.

When to Seek Help and Warning Signs to Watch For

Most men tolerate tadalafil and eplerenone together well, but you should know the warning signs that need urgent attention. 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 indicate a heart problem [1]. If you have an erection lasting more than four hours (priapism), seek urgent help, as this can cause permanent damage if not treated quickly [4]. Sudden loss of vision in one or both eyes or sudden decrease or loss of hearing are rare but serious side effects that require immediate medical attention [4].

If you feel severely dizzy, faint, or have a very fast or irregular heartbeat, contact your GP or call 111 for advice. These symptoms could indicate that your blood pressure has dropped too low or that there is another problem that needs assessment. Remember, erectile dysfunction can be an early warning sign of heart disease or diabetes, so if you have new or worsening ED, see your GP for a full check-up [1][2]. Your GP can investigate underlying causes, optimise your cardiovascular treatment, and work with you to find the safest and most effective ED treatment.

Can I Take Other ED Medicines with Eplerenone?

The same principles apply to other PDE5 inhibitors such as sildenafil (Viagra), vardenafil (Levitra), and avanafil (Spedra). All PDE5 inhibitors can lower blood pressure and may have an additive effect when combined with eplerenone or other blood-pressure medicines [3][5][6]. Your prescriber will assess each medicine individually, taking into account its specific properties, duration of action, and your overall health. Never take more than one PDE5 inhibitor at the same time, and always declare all your current medicines during your consultation. Cured Pharmacy offers a range of ED treatments, and our UK prescribers will help you choose the most suitable option based on your medical history and current medicines.

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. Joint Formulary Committee. (n.d.). Alprostadil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/alprostadil/ [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.