Tadalafil and Bendroflumethiazide: Can You Take Them Together?

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Tadalafil and Bendroflumethiazide: Understanding the Interaction

Published: 18 October 2026

Many men wonder whether tadalafil and bendroflumethiazide can be taken together safely. The good news is that tadalafil (the active ingredient in Cialis) can usually be prescribed alongside bendroflumethiazide, a thiazide diuretic commonly used to treat high blood pressure, but your prescriber will carefully check your blood pressure and overall cardiovascular health first. Both medicines can lower blood pressure, so understanding how they interact and what precautions to take is essential for safe and effective treatment.

What is tadalafil and bendroflumethiazide used for?

Tadalafil is a phosphodiesterase type 5 (PDE5) inhibitor licensed in the UK to treat erectile dysfunction (ED) [4]. It works 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 daily low-dose tablet (2.5 mg or 5 mg). It requires sexual stimulation to work and does not cause spontaneous erections [4].

Bendroflumethiazide is a thiazide diuretic (water tablet) prescribed to treat high blood pressure (hypertension) and fluid retention (oedema). It works by helping your kidneys remove excess salt and water from your body, which lowers the volume of fluid in your blood vessels and reduces blood pressure. Bendroflumethiazide is usually taken once daily in the morning. High blood pressure is a common condition, and keeping it well controlled reduces your risk of heart attack, stroke, and kidney problems.

It is quite common for men with high blood pressure to also experience erectile dysfunction. In fact, ED can sometimes be an early warning sign of cardiovascular disease [1]. This is why many men take both a blood pressure medicine like bendroflumethiazide and an ED treatment like tadalafil at the same time.

How do tadalafil and bendroflumethiazide interact?

Tadalafil and bendroflumethiazide do not have a direct drug-to-drug interaction that makes them unsafe to take together. However, both medicines can lower blood pressure, and when taken in combination, this blood-pressure-lowering effect may be additive [4]. In plain English, this means that taking both medicines together might cause your blood pressure to drop more than it would with either medicine alone.

For most men whose blood pressure is well controlled on bendroflumethiazide, this additive effect is usually manageable and does not cause problems. Tadalafil's effect on blood pressure is generally modest and short-lived, especially at the doses used for erectile dysfunction. However, if your blood pressure drops too much, you may experience symptoms such as dizziness, light-headedness (especially when standing up quickly), or feeling faint.

This is why your prescriber will always check your current blood pressure readings, review your full list of medicines (including bendroflumethiazide and any other blood pressure tablets), and assess your cardiovascular health before prescribing tadalafil. If you are taking multiple blood pressure medicines or your blood pressure is not yet stable, your prescriber may start you on a lower dose of tadalafil or advise additional monitoring. It is important to be honest about all your current medicines during your consultation so that your treatment can be tailored safely to you.

What does your prescriber check before prescribing tadalafil with bendroflumethiazide?

Before prescribing tadalafil to someone taking bendroflumethiazide, a UK prescriber will carry out a thorough clinical assessment [2]. This includes reviewing your medical history, current medicines, blood pressure readings, and any symptoms of cardiovascular disease. The prescriber needs to ensure that sexual activity itself is safe for you, as it places extra demand on your heart and circulation.

Your prescriber will specifically ask about your blood pressure control. If your blood pressure is well managed on bendroflumethiazide and you have no symptoms of low blood pressure (such as dizziness or fainting), tadalafil is usually considered safe to prescribe. However, if you are taking multiple blood pressure medicines (for example, bendroflumethiazide plus an ACE inhibitor or calcium-channel blocker), the prescriber will be extra cautious and may recommend starting with the lowest effective dose of tadalafil.

The prescriber will also check for any absolute contraindications to tadalafil, such as recent heart attack or stroke, unstable angina, severe heart failure, very low blood pressure, or the use of nitrate medicines (GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, or recreational drugs known as 'poppers' [4]. If you are taking any of these, you must not take tadalafil. The prescriber will also ask about any history of sudden vision or hearing loss, as these are rare but serious side effects that require immediate medical attention.

Declaring all your medicines during the consultation

It is essential to list every medicine you take during your online consultation, including prescription medicines, over-the-counter treatments, herbal supplements, and vitamins. This includes bendroflumethiazide and any other blood pressure tablets, as well as medicines for other conditions such as diabetes, high cholesterol, or prostate problems. Some medicines can interact with tadalafil or affect how well it works, so full disclosure helps your prescriber make the safest decision for you.

Never stop or change a prescribed medicine like bendroflumethiazide without speaking to your GP or prescriber first. If you experience any new symptoms or side effects after starting tadalafil, contact your prescriber or GP for advice.

Practical advice for taking tadalafil and bendroflumethiazide together

If you have been prescribed tadalafil while taking bendroflumethiazide, there are some practical steps you can take to minimise the risk of side effects. First, take both medicines exactly as prescribed. Bendroflumethiazide is usually taken once daily in the morning, while tadalafil can be taken on-demand (at least 30 minutes before sexual activity) or daily, depending on which regimen your prescriber has recommended.

Be aware of the signs of low blood pressure, especially when you first start tadalafil or if your dose is increased. These include dizziness, light-headedness, feeling faint, or blurred vision. If you experience these symptoms, sit or lie down until they pass, and avoid standing up quickly. If symptoms are severe or do not go away, contact your GP or NHS 111 for advice. Avoid drinking large amounts of alcohol when taking tadalafil, as alcohol can also lower blood pressure and make side effects more likely [4].

Stay well hydrated, especially in hot weather or if you are exercising, as bendroflumethiazide can increase urination and tadalafil works best when you are well hydrated. If you are taking tadalafil on-demand, plan ahead and take it at the recommended time before sexual activity (at least 30 minutes, though some men find it works better after an hour or two). Remember that tadalafil requires sexual stimulation to work—it will not cause an erection on its own.

Monitoring your blood pressure at home

If you have a home blood pressure monitor, it can be helpful to check your blood pressure regularly, especially when you first start taking tadalafil. Keep a record of your readings and share them with your GP or prescriber at your next review. This helps ensure that your blood pressure remains well controlled and that the combination of bendroflumethiazide and tadalafil is working safely for you.

If you notice a significant drop in your blood pressure or experience symptoms such as persistent dizziness or fainting, contact your GP promptly. Do not adjust your dose of either medicine without professional advice.

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

Most men take tadalafil and bendroflumethiazide together without serious problems, but it is important to know the warning signs that require urgent medical attention. If you develop chest pain or discomfort during or after sexual activity, stop what you are doing and seek immediate medical help by calling 999. Do not take GTN spray or any nitrate medicine if you have taken tadalafil, as the combination can cause a dangerous drop in blood pressure [4].

If you experience an erection that lasts longer than four hours (known as priapism), go to your nearest accident and emergency (A&E) department immediately. Priapism is a medical emergency that requires urgent treatment to prevent permanent damage to the penis. Other serious but rare side effects of tadalafil include sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing (sometimes with ringing in the ears or dizziness). If either of these occurs, stop taking tadalafil and seek medical help straight away [4].

If you experience severe dizziness, fainting, or a very fast or irregular heartbeat, contact your GP urgently or call NHS 111. These symptoms could indicate that your blood pressure has dropped too low or that there is another problem that needs assessment. Always be honest with healthcare professionals about all the medicines you are taking, including tadalafil and bendroflumethiazide, so they can provide the safest and most effective care.

Getting tadalafil safely with bendroflumethiazide at Cured Pharmacy

At Cured Pharmacy, we offer a safe and discreet online service for men who need treatment for erectile dysfunction, including those taking blood pressure medicines like bendroflumethiazide. All our ED treatments are prescription-only and require an online consultation that is reviewed by a UK-registered prescriber. During the consultation, you will be asked about your medical history, current medicines (including bendroflumethiazide and any other blood pressure tablets), and any symptoms or health concerns. This ensures that tadalafil is safe and appropriate for you.

We stock a range of tadalafil products to suit different needs and budgets. Our generic tadalafil is available from £7.95 (or £6.36 for your first order with code Ednew), and we also offer branded Cialis from £12.00 (£9.60 with code Ednew). Tadalafil 20 mg (Teva) is priced at £9.99 (£7.99 with code Ednew), and Avarante (tadalafil) 10 mg costs £11.49 (£9.19 with code Ednew). If tadalafil is not suitable for you, we also offer other PDE5 inhibitors such as sildenafil (from £0.45, or £0.36 with code Ednew), vardenafil (£16.95, or £13.56 with code Ednew), and Spedra (avanafil) (£20.95, or £16.76 with code Ednew) [3][5][6].

Once your consultation is approved, your medicine is dispensed by our GPhC-registered pharmacy (GPhC 9012511) and delivered discreetly to your door. If you have any questions about taking tadalafil with bendroflumethiazide, our pharmacist-led team is here to help. We encourage you to also see your GP for a full health check if you have not done so recently, as erectile dysfunction can sometimes be an early sign of underlying health conditions such as heart disease or diabetes [1][2].

Why choose Cured Pharmacy for your ED treatment?

Cured Pharmacy is a fully registered UK online pharmacy (GPhC 9012511) with a team of experienced pharmacists and prescribers. We understand that discussing erectile dysfunction can feel awkward, so we have designed our service to be as straightforward and discreet as possible. Our online consultation takes just a few minutes to complete, and most consultations are reviewed within 24 hours. All medicines are dispensed by our registered pharmacy and sent in plain, unmarked packaging.

We are committed to providing safe, evidence-based care. If tadalafil is not suitable for you—for example, if your blood pressure is not well controlled or you are taking a medicine that interacts with tadalafil—our prescribers will let you know and suggest alternative options or advise you to see your GP. Your health and safety are always our top priority.

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. Joint Formulary Committee. (n.d.). Vardenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/vardenafil/ [accessed 18 October 2026]
6. Joint Formulary Committee. (n.d.). Avanafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/avanafil/ [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.