Tadalafil and Acarbose: Can You Take Them Together?

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Tadalafil and Acarbose: Understanding the Interaction

Published: 18 October 2026

Many men taking tadalafil and acarbose together wonder whether the combination is safe. The good news is that no major direct interaction between tadalafil (a medicine for erectile dysfunction) and acarbose (a diabetes medicine) is commonly reported in clinical practice. However, because both conditions—diabetes and erectile dysfunction—are closely linked, and because all medicines can affect the body in different ways, your prescriber will carefully review your full medication list and health history during your consultation.

What is tadalafil and acarbose used for?

Tadalafil is a prescription medicine used to treat erectile dysfunction (ED) in men [3][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 are sexually aroused. Tadalafil is available as on-demand tablets (10 mg or 20 mg, taken at least 30 minutes before sex, with effects lasting up to 36 hours) or as a lower daily dose (2.5 mg or 5 mg) for men who prefer not to plan ahead [4]. Sexual stimulation is still needed for the medicine to work.

Acarbose is a prescription medicine used to manage type 2 diabetes [12]. It works by slowing down the digestion and absorption of carbohydrates in your gut, which helps prevent sharp rises in blood sugar after meals. Acarbose is often prescribed alongside diet, exercise, and sometimes other diabetes medicines such as metformin or insulin. Because diabetes is a common underlying cause of erectile dysfunction, many men find themselves taking both an ED treatment and a diabetes medicine at the same time [1][2].

How do tadalafil and acarbose interact?

There is no well-documented pharmacological interaction between tadalafil and acarbose that would make the combination unsafe [3][4][12]. Acarbose works in the digestive system to slow carbohydrate absorption, while tadalafil acts on blood vessels and is metabolised mainly by the liver. They use different pathways in the body and do not directly interfere with each other's action or breakdown.

That said, diabetes itself—especially if poorly controlled—can contribute to or worsen erectile dysfunction by damaging blood vessels and nerves over time [1][2]. Good blood sugar control, supported by medicines like acarbose, may actually help improve erectile function in the longer term. Your prescriber will want to know about your diabetes management, your current blood sugar levels, and any complications (such as heart or kidney problems) because these factors influence whether tadalafil is suitable and at what dose [2][4].

Why your full medication list matters

Even though acarbose and tadalafil do not interact directly, other medicines you take for diabetes or its complications might. For example, some men with diabetes also take blood pressure tablets (such as alpha-blockers or ACE inhibitors), which can add to the blood-pressure-lowering effect of tadalafil and cause dizziness [3][4]. Your prescriber checks every medicine during your online consultation to ensure the combination is safe for you personally.

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

During your online consultation at Cured Pharmacy, the prescriber will review your full medical history and current medicines [2]. They will ask about your diabetes control, including your most recent HbA1c or blood sugar readings, and whether you have any diabetes-related complications such as heart disease, high blood pressure, kidney problems, or nerve damage (neuropathy). These conditions can affect whether tadalafil is safe and which dose is appropriate [4].

The prescriber will also check for any contraindicated medicines. You must never take tadalafil if you are using nitrates (such as GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, or recreational drugs known as 'poppers' (amyl or alkyl nitrites), because the combination can cause a dangerous drop in blood pressure [3][4]. If you take an alpha-blocker (for example, tamsulosin for prostate symptoms or doxazosin for blood pressure), you should be stable on that medicine and start tadalafil at the lowest dose to minimise the risk of dizziness [4].

Finally, the prescriber will confirm that sexual activity is safe for you. If you have had a recent heart attack or stroke, unstable angina, severe heart failure, or very low blood pressure, tadalafil may not be suitable [2][4]. Declaring all your medicines and health conditions honestly ensures you receive safe, personalised advice.

Practical advice for taking tadalafil and acarbose safely

If your prescriber approves tadalafil, take it exactly as directed. For on-demand tadalafil (10 mg or 20 mg), swallow the tablet at least 30 minutes before you plan to have sex; the effect can last up to 36 hours, so you do not need to rush [4]. For daily tadalafil (2.5 mg or 5 mg), take one tablet at the same time each day, whether or not you plan sexual activity. You can take tadalafil with or without food, and it does not interfere with the timing of your acarbose doses.

Continue taking acarbose as prescribed by your diabetes team, usually with the first bite of each main meal [12]. Do not stop or change your diabetes medicine without medical advice, as good blood sugar control is important for your overall health and can help improve erectile function over time [1][2]. Monitor for any new symptoms: if you feel dizzy or light-headed when standing up, sit or lie down and tell your GP or prescriber, as this may indicate low blood pressure.

Avoid drinking large amounts of alcohol, as heavy drinking can worsen erectile dysfunction and add to the blood-pressure-lowering effect of tadalafil [3][4]. Grapefruit juice can raise tadalafil levels in your blood, so it is best avoided or limited. If you are prescribed a new medicine by your GP or hospital doctor, always mention that you are taking tadalafil to ensure there are no new interactions.

Lifestyle tips to support both conditions

Healthy lifestyle changes benefit both diabetes and erectile dysfunction. Aim for a balanced diet, regular physical activity, maintaining a healthy weight, and not smoking [1][2]. These steps improve blood sugar control, support cardiovascular health, and can enhance the effectiveness of tadalafil. Your GP or diabetes nurse can provide tailored advice and support.

Warning signs and when to seek help with tadalafil and acarbose

Most men tolerate tadalafil well, but you should be aware of warning signs that need urgent attention [3][4]. If you develop an erection that lasts longer than four hours (priapism), go to A&E immediately, as this can cause permanent damage if not treated promptly. Sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing (sometimes with ringing in the ears or dizziness), requires urgent medical assessment—stop taking tadalafil and seek help straight away [4].

If you experience chest pain during or after sex, do not use nitrate medicines (such as GTN spray) to relieve it, because the combination with tadalafil can be dangerous [3][4]. Instead, call 999 or go to A&E and tell the medical team you have taken tadalafil. If you feel severely dizzy, faint, or notice your heart racing or pounding, sit or lie down and contact your GP or NHS 111 for advice.

Common side effects of tadalafil include headache, indigestion, back pain, muscle aches, flushing, and a stuffy or runny nose [4]. These are usually mild and short-lived. Acarbose can cause wind, bloating, and diarrhoea, especially when you first start taking it [12]. If side effects from either medicine are troublesome or persistent, speak to your prescriber or pharmacist for advice—do not simply stop your medicine without guidance.

Getting tadalafil and acarbose: your next steps

At Cured Pharmacy, a GPhC-registered online pharmacy (GPhC 9012511), you can request tadalafil through a straightforward online consultation. A UK-registered prescriber will review your answers, including your diabetes medicines and overall health, to ensure tadalafil is safe and appropriate for you [2]. If approved, your medicine is dispensed by our pharmacist team and delivered discreetly to your door.

We offer a range of tadalafil options to suit different needs and budgets. Generic tadalafil is available from £7.95 (or £6.36 for your first order with code Ednew), branded Cialis from £12.00 (£9.60 with code Ednew), and other strengths and brands including Teva and Avarante [4]. You will continue to collect your acarbose prescription from your usual GP or diabetes clinic, as Cured Pharmacy specialises in erectile dysfunction treatments.

If you have not yet seen a doctor about your erectile dysfunction, we encourage you to book a GP appointment. ED can be an early warning sign of heart disease or poorly controlled diabetes, so it is important to have a full health check [1][2]. Your GP can also review your diabetes management and refer you to specialist services if needed. Once you have discussed ED with a healthcare professional, our online service offers a convenient way to access ongoing treatment and support.

Why choose Cured Pharmacy?

Our service is led by experienced UK pharmacists and prescribers who understand the link between diabetes and erectile dysfunction. Every consultation is reviewed individually, your privacy is protected, and our team is available to answer questions about your treatment. We are committed to providing safe, evidence-based care that fits into your life.

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. 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.