Tadalafil and Candesartan: Can You Take Them Together?

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Tadalafil and Candesartan: Understanding the Interaction

Published: 18 October 2026

Many men wonder whether tadalafil and candesartan can be taken together safely. The good news is that tadalafil, a medicine used to treat erectile dysfunction, can usually be taken alongside candesartan, a blood pressure medicine, but your prescriber will need to check your blood pressure and overall health first. This page explains how these medicines work, what the interaction means, and the 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). It belongs to a group of medicines called PDE5 inhibitors, which work by relaxing blood vessels in the penis, allowing more blood to flow in when you are sexually aroused [3][4]. Tadalafil is the generic name for Cialis and is available in two forms: on-demand tablets (10mg or 20mg) taken at least 30 minutes before sex, with effects lasting up to 36 hours, and daily low-dose tablets (2.5mg or 5mg) taken once a day [4].

Unlike some other ED treatments, tadalafil does not cause an erection on its own—you still need sexual stimulation for it to work [4]. It is licensed in the UK and has been used safely by millions of men worldwide. Tadalafil can also be prescribed for benign prostatic hyperplasia (an enlarged prostate) and pulmonary arterial hypertension, though the doses and brand names differ [4]. At Cured Pharmacy, tadalafil is available after an online consultation reviewed by a UK prescriber.

What is Candesartan and Why is It Prescribed?

Candesartan is a medicine used to treat high blood pressure (hypertension) and heart failure. It belongs to a class of medicines called angiotensin II receptor blockers (ARBs), which work by blocking the action of a hormone that narrows blood vessels, allowing them to relax and widen. This lowers blood pressure and reduces the strain on the heart. Candesartan is usually taken once a day and is often prescribed when other blood pressure medicines, such as ACE inhibitors, cause side effects like a persistent dry cough.

High blood pressure is a common condition in the UK and often has no symptoms, but if left untreated it can increase the risk of heart attack, stroke, and kidney problems. Many men with high blood pressure also experience erectile dysfunction, partly because both conditions share risk factors such as diabetes, smoking, and being overweight [1][2]. Treating high blood pressure is important for long-term health, and most men on candesartan can still use ED treatments safely with the right medical checks.

Why High Blood Pressure and ED Often Occur Together

Erectile dysfunction and high blood pressure are closely linked. Both conditions affect blood vessels, and damage to the lining of blood vessels (endothelial dysfunction) can reduce blood flow to the penis as well as raising blood pressure [1][2]. In fact, ED can sometimes be an early warning sign of cardiovascular disease, which is why it is important to see your GP if you develop new erection problems. Treating high blood pressure with medicines like candesartan can improve overall health, and many men find that their ED improves once their blood pressure is well controlled.

Can You Take Tadalafil and Candesartan Together?

Yes, tadalafil and candesartan can usually be taken together, but only under the supervision of a prescriber who will check your blood pressure and overall cardiovascular health. Both medicines can lower blood pressure, so there is a potential for an additive effect—meaning your blood pressure might drop more than it would with either medicine alone. For most men whose blood pressure is well controlled on candesartan, this is not a problem, but your prescriber will want to make sure your blood pressure is stable and not too low before approving tadalafil [3][4].

During the online consultation at Cured Pharmacy, you will be asked about all your current medicines, including candesartan, and about any symptoms such as dizziness or fainting. The prescriber will also check whether you have any conditions that make sexual activity inadvisable, such as recent heart attack, unstable angina, or severe heart failure [2][4]. If your blood pressure is well managed and you have no other risk factors, tadalafil is usually considered safe. The prescriber may recommend starting on a lower dose to minimise the risk of side effects.

How Do Tadalafil and Candesartan Interact?

The interaction between tadalafil and candesartan is pharmacodynamic, meaning both medicines affect the body in a similar way—they both relax and widen blood vessels, which can lower blood pressure. Tadalafil does this in the penis (and to a lesser extent throughout the body), while candesartan does it more generally to reduce blood pressure [3][4]. When taken together, the blood-pressure-lowering effects can add up, which may cause dizziness, light-headedness, or fainting, especially when standing up quickly.

This interaction is usually mild and manageable, especially if your blood pressure is stable and not already low. It is very different from the dangerous interaction between tadalafil and nitrates (such as GTN spray) or nicorandil, which can cause a severe and potentially life-threatening drop in blood pressure. You must never take tadalafil with nitrates, nicorandil, riociguat, or poppers [3][4]. Candesartan, however, is not contraindicated with tadalafil; the combination simply requires careful prescriber assessment and monitoring.

What Your Prescriber Will Check

Before approving tadalafil, your prescriber will review your current blood pressure readings, any symptoms of low blood pressure (such as dizziness or fainting), and your overall cardiovascular health. They will also check that you are not taking any medicines that are contraindicated with tadalafil, such as nitrates or nicorandil. If you are on a stable dose of candesartan and your blood pressure is well controlled, the prescriber may approve tadalafil at the usual starting dose or recommend a lower dose to start. You should never adjust your candesartan dose yourself to accommodate tadalafil—always follow your GP's or prescriber's advice.

Practical Advice for Taking Tadalafil with Candesartan

If you are prescribed tadalafil while taking candesartan, there are some practical steps you can take to use both medicines safely. First, continue taking your candesartan exactly as prescribed by your GP—do not stop or change the dose without medical advice, as this could cause your blood pressure to rise. Take tadalafil as directed by your prescriber, usually at least 30 minutes before sexual activity if using the on-demand dose, or once daily at the same time each day if using the daily dose [4].

Be aware of the signs of low blood pressure, such as feeling dizzy, light-headed, or faint, especially when standing up from sitting or lying down. If you experience these symptoms, sit or lie down until they pass, and mention them to your prescriber or GP. Avoid drinking large amounts of alcohol when taking tadalafil, as alcohol can lower blood pressure further and make ED worse [3][4]. Stay well hydrated, especially in hot weather or after exercise. If you develop chest pain during sex, stop immediately and seek urgent medical help—do not take nitrate medicines (GTN spray) if you have used tadalafil in the past 48 hours, as this combination is dangerous.

When to Contact Your GP or Prescriber

Contact your GP or prescriber if you experience persistent dizziness, fainting, or any new symptoms after starting tadalafil. You should also get in touch if tadalafil does not work for you, as there may be other treatment options or underlying causes of ED that need investigation [1][2]. If you develop an erection lasting more than four hours (priapism), sudden loss of vision or hearing, or chest pain during sex, seek urgent medical help immediately. These are rare but serious side effects that require prompt treatment.

Other Blood Pressure Medicines and Tadalafil

Candesartan is just one of many blood pressure medicines, and the advice for taking tadalafil applies to most other antihypertensives as well. Medicines such as ACE inhibitors (ramipril, lisinopril, perindopril), other ARBs (losartan, valsartan, irbesartan), calcium channel blockers (amlodipine, felodipine, nifedipine), and diuretics (bendroflumethiazide, indapamide) can all be taken with tadalafil, provided your blood pressure is stable and your prescriber approves [3][4].

Alpha-blockers (such as doxazosin, tamsulosin, and alfuzosin), which are used for high blood pressure and prostate symptoms, require extra caution. These medicines can interact more significantly with tadalafil, increasing the risk of dizziness and low blood pressure. If you take an alpha-blocker, you must be stable on it before starting tadalafil, and your prescriber will usually recommend the lowest dose of tadalafil to start [3][4]. Always declare all your medicines during the consultation, including over-the-counter and herbal products, so the prescriber can check for interactions.

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]

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.