Tadalafil and Indometacin: Can You Take Them Together?

Tadalafil and Indometacin: Understanding the Interaction

Published: 22 October 2026

Many men wonder whether tadalafil and indometacin can be taken together safely. The good news is that there is no major, well-documented interaction between tadalafil (a medicine for erectile dysfunction) and indometacin (a non-steroidal anti-inflammatory drug, or NSAID). However, both medicines can affect your cardiovascular system in different ways, so your prescriber will carefully review your full medical history and current medicines during your consultation to ensure the combination is suitable for you personally.

What is tadalafil and indometacin?

Tadalafil is a prescription medicine used to treat erectile dysfunction (ED) in men [4]. 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. Tadalafil is available as an on-demand treatment (10 mg or 20 mg taken at least 30 minutes before sexual activity, with effects lasting up to 36 hours) or as a daily low-dose tablet (2.5 mg or 5 mg) [4]. You may know tadalafil by its brand name, Cialis.

Indometacin (sometimes spelled indomethacin) is a non-steroidal anti-inflammatory drug (NSAID) used to relieve pain, reduce inflammation, and lower fever. It is commonly prescribed for conditions such as arthritis, gout, muscle pain, and other inflammatory disorders. Indometacin works by blocking enzymes (called COX enzymes) that produce chemicals in the body responsible for pain, swelling, and inflammation. It is available in various forms, including capsules, tablets, and suppositories, and is usually taken with or after food to reduce the risk of stomach upset.

Do tadalafil and indometacin interact with each other?

There is no major, clinically significant interaction commonly reported between tadalafil and indometacin when used together [3][4]. This means that, for most people, taking both medicines at the same time does not lead to a dangerous or harmful effect. Unlike the serious interaction between tadalafil and nitrate medicines (such as GTN spray or isosorbide mononitrate), which can cause a dangerous drop in blood pressure, indometacin does not directly interfere with how tadalafil works in your body.

However, both medicines can have effects on your cardiovascular system. Tadalafil can cause a modest reduction in blood pressure, which is usually well tolerated but may cause dizziness or light-headedness in some men [4]. Indometacin, like other NSAIDs, can sometimes raise blood pressure slightly or cause fluid retention, particularly if used for long periods or at high doses. In people with existing heart or kidney problems, NSAIDs may also increase the risk of cardiovascular events. For this reason, your prescriber will carefully assess your overall health, blood pressure, and any other medicines you take before approving tadalafil, even if indometacin itself does not directly interact with it.

How the interaction mechanism works (in plain English)

Tadalafil works by blocking an enzyme called PDE5, which leads to relaxation of blood vessels and improved blood flow to the penis during sexual arousal [4]. This same mechanism can also cause a small drop in blood pressure throughout the body. Indometacin, on the other hand, reduces inflammation by blocking COX enzymes, but it can also affect the kidneys' ability to regulate salt and water balance, which may lead to a slight rise in blood pressure or fluid retention in some people. These two effects—tadalafil lowering blood pressure and indometacin potentially raising it—do not cancel each other out in a predictable way, and the overall impact depends on your individual health, dose, and how long you have been taking each medicine.

What does your prescriber check before approving tadalafil and indometacin together?

When you request tadalafil through an online consultation at Cured Pharmacy, a UK-registered prescriber will review your full medical history and all current medicines, including indometacin [2]. They will check your blood pressure, heart health, and kidney function, because both tadalafil and NSAIDs like indometacin can affect these systems. If you have a history of heart disease, stroke, uncontrolled high blood pressure, or kidney problems, the prescriber may need to adjust your dose, recommend a different treatment, or advise you to see your GP for further assessment before starting tadalafil.

The prescriber will also ask about any other medicines you take, because some combinations are not safe. For example, you must never take tadalafil with nitrate medicines (such as GTN spray, isosorbide mononitrate, or isosorbide dinitrate), nicorandil, riociguat, or recreational drugs called 'poppers' (amyl or alkyl nitrites), as these can cause a dangerous fall in blood pressure [4]. If you are taking alpha-blockers (such as doxazosin or tamsulosin) for prostate problems, you will need to be stable on that medicine and start tadalafil at the lowest dose. Potent CYP3A4 inhibitors (such as ritonavir, ketoconazole, or clarithromycin) can raise tadalafil levels in your blood, so your dose may need to be reduced [4].

It is essential to list every medicine you take—prescription, over-the-counter, herbal, and recreational—during your consultation, so the prescriber can make a safe, informed decision.

Practical advice for taking tadalafil and indometacin safely

If your prescriber approves tadalafil while you are taking indometacin, follow the dosing instructions carefully. Take tadalafil on-demand tablets (10 mg or 20 mg) at least 30 minutes before sexual activity, and do not take more than one dose in 24 hours [4]. If you are prescribed daily tadalafil (2.5 mg or 5 mg), take it at the same time each day, with or without food. Tadalafil only works when you are sexually aroused, so it will not cause an erection on its own.

Take indometacin exactly as your doctor has prescribed, usually with or after food to protect your stomach. Do not exceed the recommended dose or duration, as long-term use of NSAIDs can increase the risk of stomach ulcers, kidney problems, and cardiovascular events. If you experience dizziness, light-headedness, or a significant drop in blood pressure after taking tadalafil, sit or lie down until you feel better, and avoid driving or operating machinery. Drinking large amounts of alcohol can make erectile dysfunction worse and add to the blood-pressure-lowering effect of tadalafil, so limit your alcohol intake [4].

Do not stop or change your indometacin or any other prescribed medicine without speaking to your doctor or pharmacist first. If you develop new symptoms, such as severe stomach pain, black or bloody stools, swelling of the ankles, or chest pain, seek medical advice promptly.

Monitoring and when to contact your GP

If you are taking both tadalafil and indometacin, it is a good idea to monitor your blood pressure at home if you have access to a monitor, especially if you have a history of high blood pressure or heart disease. If your blood pressure becomes consistently high or low, or if you feel unwell, contact your GP. You should also see your GP if you experience new or worsening symptoms such as chest pain, shortness of breath, severe headache, or sudden changes in vision or hearing while taking tadalafil [4]. Remember that erectile dysfunction can be an early warning sign of heart disease or diabetes, so it is important to have regular check-ups with your doctor [1][2].

Warning signs and when to seek urgent help with tadalafil and indometacin

Most men tolerate tadalafil and indometacin well when taken together, but you should be aware of warning signs that require urgent medical attention. If you develop an erection that lasts longer than four hours (a condition called priapism), go to your nearest accident and emergency (A&E) department immediately, as this can cause permanent damage to the penis if not treated quickly [4]. Sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing (sometimes with ringing in the ears or dizziness), are rare but serious side effects of PDE5 inhibitors and require urgent medical help [4].

If you experience chest pain during or after sexual activity, stop and seek medical advice straight away, as this may indicate a heart problem [4]. Severe stomach pain, vomiting blood, or passing black, tarry stools while taking indometacin may be signs of a stomach ulcer or bleeding and require immediate medical attention. Swelling of the face, lips, tongue, or throat, or difficulty breathing, may indicate a severe allergic reaction; call 999 if this happens. If you feel very dizzy, faint, or have a severe headache after taking tadalafil, especially if you have also taken indometacin or other medicines, seek medical advice promptly.

Getting tadalafil safely through Cured Pharmacy

At Cured Pharmacy, all prescription medicines, including tadalafil, are only supplied after a confidential online consultation reviewed by a UK-registered prescriber. During the consultation, you will be asked about your medical history, current medicines (including indometacin and any other NSAIDs), and any health conditions that might affect the safety of tadalafil. The prescriber will check for any contraindications or interactions and ensure that tadalafil is suitable for you [2][4].

If approved, your medicine will be dispensed by our GPhC-registered pharmacy (GPhC 9012511) and delivered discreetly to your door. We offer a range of tadalafil options, including generic and branded versions, at transparent prices. You can also speak to our pharmacist team if you have any questions about taking tadalafil with indometacin or any other medicine. We encourage you to see your GP if you have not already done so, as erectile dysfunction can be a sign of underlying health problems such as diabetes, high blood pressure, or heart disease, and early diagnosis and treatment can improve your overall health and wellbeing [1][2].

Never buy tadalafil from unregistered websites or without a prescription, as counterfeit or unlicensed medicines can be dangerous and may not contain the correct active ingredient. Always use a registered UK pharmacy and ensure that a qualified prescriber has reviewed your medical history before you start treatment.

Other NSAIDs and tadalafil

If you take other NSAIDs—such as ibuprofen, naproxen, diclofenac, or celecoxib—the same principles apply. There is no major, direct interaction between these medicines and tadalafil, but your prescriber will still review your cardiovascular health, blood pressure, and kidney function before approving tadalafil [3][4]. Long-term or high-dose use of any NSAID can increase the risk of heart and kidney problems, so always use the lowest effective dose for the shortest time necessary, and discuss any concerns with your doctor or pharmacist.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 22 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 22 October 2026]
3. Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 22 October 2026]
4. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 22 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.