Tadalafil and Prasugrel: Can You Take Them Together?

Tadalafil and Prasugrel: Understanding the Interaction

Published: 24 October 2026

Many men wonder whether tadalafil and prasugrel can be taken together safely. The good news is that no major direct interaction is commonly reported between tadalafil (a treatment for erectile dysfunction) and prasugrel (an antiplatelet medicine used to prevent blood clots after heart attack or stent procedures). However, because both medicines can affect your cardiovascular system, your prescriber will carefully review your full medical history and current medications during your consultation to ensure the combination is appropriate for you.

What Is Tadalafil?

Tadalafil is a prescription medicine licensed in the UK 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 the active ingredient in branded Cialis and is also available as a lower-cost generic.

Tadalafil is available in two forms: on-demand tablets (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) taken once a day [4]. All forms require sexual stimulation to work—they do not cause an automatic erection. Tadalafil is only supplied after an online or face-to-face consultation with a UK-registered prescriber, who will check your medical history and current medicines.

What Is Prasugrel?

Prasugrel is a prescription antiplatelet medicine used to prevent blood clots in people who have had a heart attack or who have undergone a procedure to open blocked coronary arteries (such as stent placement). It works by stopping platelets in your blood from sticking together, which reduces the risk of clots forming in your arteries. Prasugrel is usually prescribed alongside aspirin as part of dual antiplatelet therapy.

Because prasugrel affects blood clotting, it increases the risk of bleeding. Common side effects include bruising more easily and nosebleeds. More serious bleeding (such as stomach bleeding or bleeding in the brain) is rare but requires urgent medical attention. Your doctor will have prescribed prasugrel because the benefits of preventing a heart attack or stroke outweigh the bleeding risk in your situation. You should never stop taking prasugrel without consulting your doctor, as stopping suddenly can increase your risk of a clot.

How Do Tadalafil and Prasugrel Interact?

There is no major direct pharmacological interaction commonly reported between tadalafil and prasugrel. They work through different mechanisms in the body: tadalafil relaxes blood vessels to improve blood flow to the penis, while prasugrel prevents platelets from clumping together to form clots. Neither medicine is known to significantly alter the blood levels or effectiveness of the other.

However, both medicines can affect your cardiovascular system in different ways. Tadalafil can cause a small drop in blood pressure, which is usually mild and well-tolerated, but may cause dizziness or light-headedness in some men [4]. Prasugrel does not directly lower blood pressure, but the fact that you are taking it means you have a history of heart disease or have had a heart procedure. Your prescriber will need to assess whether your heart is healthy enough for sexual activity and whether tadalafil is safe for you, taking into account your full cardiovascular history and any other medicines you take.

What Your Prescriber Will Check

During your consultation, the prescriber will ask about your heart condition, when you had your heart attack or stent procedure, and whether you have any symptoms such as chest pain or breathlessness. They will also check all your current medicines, including prasugrel, aspirin, and any blood-pressure tablets. If you have unstable angina, severe heart failure, or have had a recent heart attack or stroke, tadalafil may not be suitable [4]. The prescriber will also confirm that you are not taking any medicines that must never be combined with tadalafil, such as nitrates (GTN spray, isosorbide mononitrate), nicorandil, or riociguat, as these combinations can cause a dangerous drop in blood pressure.

Practical Advice for Taking Tadalafil and Prasugrel Together

If your prescriber approves tadalafil for you, take it exactly as directed. For on-demand tadalafil, take one tablet at least 30 minutes before sexual activity; do not take more than one dose in 24 hours [4]. For daily tadalafil, take one tablet at the same time each day. Continue taking prasugrel and any other heart medicines exactly as your doctor has prescribed—do not stop or change the dose without medical advice.

Be aware of how you feel when you first take tadalafil. If you experience dizziness, light-headedness, or feel faint, sit or lie down until it passes. Avoid heavy alcohol, as it can make these symptoms worse and may also make it harder to get an erection. If you develop chest pain during or after sexual activity, stop and seek urgent medical help. Do not take a nitrate medicine (such as GTN spray) if you have taken tadalafil in the past 48 hours, as this combination is dangerous. Tell the paramedics or A&E staff that you have taken tadalafil.

Other Medicines and Tadalafil Interactions

While prasugrel and tadalafil do not have a major direct interaction, it is important to be aware of other medicines that can interact with tadalafil. Never take tadalafil with nitrates (GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, or recreational drugs called 'poppers' (amyl or alkyl nitrites), as the combination can cause a severe and dangerous drop in blood pressure [4]. Do not take tadalafil with another PDE5 inhibitor such as sildenafil (Viagra), vardenafil (Levitra), or avanafil (Spedra).

Alpha-blockers (such as doxazosin, tamsulosin, or alfuzosin, used for prostate or blood-pressure problems) can also lower blood pressure when combined with tadalafil, so your prescriber will start you on a low dose if you take these medicines [4]. Some antibiotics and antifungal medicines (such as clarithromycin, erythromycin, ketoconazole, or itraconazole) can raise tadalafil levels in your blood, so your prescriber may adjust your dose. Always tell your prescriber and pharmacist about every medicine you take, including over-the-counter products and herbal supplements.

Grapefruit and Alcohol

Grapefruit and grapefruit juice can increase the levels of tadalafil in your blood, which may raise the risk of side effects such as headache, flushing, or dizziness. It is best to avoid grapefruit products while taking tadalafil. Drinking large amounts of alcohol can make it harder to get an erection and can also add to the blood-pressure-lowering effect of tadalafil, increasing the risk of dizziness or fainting. Limit alcohol to one or two units if you plan to take tadalafil.

When to Seek Urgent Medical Help

Seek immediate medical help (call 999 or go to A&E) if you experience an erection that lasts longer than four hours (priapism), even if it is painful. This is a medical emergency that requires urgent treatment to prevent permanent damage to the penis [4]. Also seek urgent help if you have sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing, which may be accompanied by ringing in the ears or dizziness.

If you develop chest pain, severe dizziness, or feel faint during or after sexual activity, stop and seek urgent medical attention. Tell the healthcare professionals that you have taken tadalafil and that you are on prasugrel and other heart medicines. Do not take a nitrate medicine (such as GTN spray) if you have used tadalafil in the past 48 hours. If you experience unusual or severe bleeding (such as blood in your urine or stools, vomiting blood, or a severe nosebleed that will not stop), this may be related to prasugrel and you should contact your doctor or call 111 for advice.

Reporting Side Effects

Common side effects of tadalafil include headache, indigestion, back pain, muscle aches, flushing, and a blocked or runny nose [4]. These are usually mild and go away on their own. If side effects are troublesome or persistent, speak to your pharmacist or prescriber. You can report side effects via the UK Yellow Card Scheme at https://yellowcard.mhra.gov.uk or by searching for 'Yellow Card' in the Google Play or Apple App Store. Reporting side effects helps improve the safety information available about medicines.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 24 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 24 October 2026]
3. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 24 October 2026]
4. Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 24 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.