Tadalafil and Valsartan: Can You Take Them Together?

Tadalafil and Valsartan: Understanding the Interaction

Published: 26 October 2026

Many men wonder whether tadalafil and valsartan can be taken together safely. The good news is that tadalafil, a medicine for erectile dysfunction, is not contraindicated with valsartan, a blood-pressure medicine, but the combination does require careful prescriber assessment because both medicines can lower blood pressure. This page explains what each medicine does, how they interact, what checks your prescriber will carry out, and the practical steps you can take to use them safely.

What Is Tadalafil and How Does It Work?

Tadalafil is a prescription medicine used to treat erectile dysfunction (ED) in men [3][4]. It belongs to a group of medicines called phosphodiesterase type 5 (PDE5) inhibitors, which work by relaxing the blood vessels in the penis, allowing increased blood flow when you are sexually aroused. Tadalafil does not cause an erection on its own—sexual stimulation is still needed for it to work [4].

Tadalafil is available in two forms: on-demand tablets (usually 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 regardless of when you plan to have sex [4]. The branded version is known as Cialis, but generic tadalafil is widely available and works in exactly the same way. At Cured Pharmacy, tadalafil is available on prescription after an online consultation reviewed by a UK prescriber.

Because tadalafil relaxes blood vessels throughout the body—not just in the penis—it can cause a modest drop in blood pressure [4]. This effect is usually mild and well tolerated, but it becomes important when tadalafil is combined with other medicines that also lower blood pressure, such as valsartan.

What Is Valsartan and Why Is It Prescribed?

Valsartan is a prescription medicine used to treat high blood pressure (hypertension) and sometimes heart failure [12]. 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, thereby allowing the vessels to relax and blood pressure to fall [12].

High blood pressure is a common condition, especially in men over 40, and it often has no symptoms. Left untreated, it increases the risk of heart attack, stroke, and kidney disease. Valsartan is usually taken once or twice a day, and it may be prescribed on its own or in combination with other blood-pressure medicines such as a diuretic (water tablet) or a calcium-channel blocker [12].

Because valsartan lowers blood pressure, combining it with other medicines that have the same effect—including tadalafil—can sometimes lead to an additive drop in blood pressure. This does not mean the combination is unsafe, but it does mean your prescriber will need to assess your overall cardiovascular health and current blood-pressure control before approving tadalafil.

Can You Take Tadalafil and Valsartan Together?

Yes, tadalafil and valsartan can be taken together, and this combination is commonly prescribed [4][12]. There is no absolute contraindication between the two medicines, meaning they are not forbidden to use at the same time. However, because both medicines can lower blood pressure, there is a risk of an additive effect that may cause dizziness, light-headedness, or fainting, particularly when standing up quickly [4].

The interaction works like this: valsartan relaxes and widens your blood vessels to reduce blood pressure, and tadalafil also causes blood vessels to relax (primarily to improve blood flow to the penis, but with a mild effect on overall blood pressure). When taken together, the combined blood-pressure-lowering effect can be greater than either medicine alone. For most men whose blood pressure is well controlled on valsartan, this additive effect is small and manageable, but it must be assessed on an individual basis [4][12].

Your prescriber will review your current blood-pressure readings, the dose of valsartan you are taking, any other blood-pressure medicines you use, and your overall heart health. If your blood pressure is stable and well controlled, tadalafil is usually considered safe to prescribe. The prescriber may recommend starting on a lower dose of tadalafil (such as 10 mg on-demand or 2.5 mg daily) to minimise the risk of low blood pressure, and they will advise you on warning signs to watch for [4].

How the Interaction Is Managed in Practice

During your online consultation at Cured Pharmacy, the prescriber will ask about your current blood-pressure control, any symptoms of low blood pressure (such as dizziness or fainting), and whether you have any heart or circulation problems. If you are stable on valsartan and your blood pressure is within the target range, tadalafil is usually approved. The prescriber may suggest you take tadalafil at a time when you can sit or lie down if you feel dizzy, and to avoid sudden changes in posture (such as standing up quickly from sitting or lying) for a few hours after taking the tablet [4]. If you experience persistent dizziness, light-headedness, or fainting, you should contact your GP or prescriber for review.

What Your Prescriber Checks Before Approving Tadalafil and Valsartan

Before prescribing tadalafil to someone taking valsartan, the prescriber will carry out a thorough assessment to ensure the combination is safe for you [2][4]. This includes reviewing your current blood-pressure readings (ideally measured at home or by your GP), the dose and duration of your valsartan treatment, and whether your blood pressure is stable and well controlled. If your blood pressure is too low (hypotension) or poorly controlled, tadalafil may not be suitable until your blood pressure is optimised [4].

The prescriber will also ask about any other medicines you take, particularly other blood-pressure medicines (such as amlodipine, ramipril, or bendroflumethiazide), because multiple blood-pressure-lowering drugs together increase the risk of dizziness and fainting [4]. They will check for any history of heart disease, including recent heart attack, unstable angina, severe heart failure, or stroke, as these conditions may make sexual activity inadvisable and tadalafil unsuitable [2][4].

You will be asked about any symptoms of low blood pressure, such as dizziness when standing, fainting spells, or feeling light-headed. The prescriber will also confirm that you are not taking any medicines that are absolutely contraindicated with tadalafil, such as nitrates (GTN spray, isosorbide mononitrate), nicorandil, riociguat, or recreational drugs known as 'poppers' (amyl or alkyl nitrites), as combining these with tadalafil can cause a dangerous drop in blood pressure [3][4]. If all checks are satisfactory, the prescriber will approve tadalafil, often starting at a lower dose to minimise risk.

Starting Dose and Monitoring

For men taking valsartan or other blood-pressure medicines, the prescriber may recommend starting tadalafil at the lower end of the dose range—such as 10 mg on-demand rather than 20 mg, or 2.5 mg daily rather than 5 mg—to reduce the chance of a significant drop in blood pressure [4]. You can then monitor how you feel after the first dose or two. If you tolerate the lower dose well without dizziness or other side effects, and if it is effective for your erectile dysfunction, you may continue at that dose. If the effect is insufficient and you have had no problems with blood pressure, the prescriber may consider increasing the dose at a follow-up consultation [4].

Practical Advice for Taking Tadalafil with Valsartan

If you have been prescribed tadalafil while taking valsartan, there are several practical steps you can take to use both medicines safely and effectively. First, take each medicine exactly as prescribed: valsartan is usually taken once or twice daily at the same time each day, while on-demand tadalafil is taken at least 30 minutes before planned sexual activity (and no more than once in 24 hours), or daily tadalafil is taken once a day at the same time [4][12].

Be aware of the signs of low blood pressure, which include feeling dizzy or light-headed (especially when standing up), fainting, blurred vision, nausea, or unusual tiredness [4]. If you notice these symptoms after taking tadalafil, sit or lie down until you feel better, and avoid driving or operating machinery. If symptoms are severe or persistent, contact your GP or prescriber. To reduce the risk of dizziness, avoid standing up quickly from a sitting or lying position, particularly in the first few hours after taking tadalafil [4].

Limit alcohol intake when using tadalafil, as heavy drinking can worsen erectile dysfunction, increase the risk of side effects such as dizziness and headache, and add to the blood-pressure-lowering effect [4]. One or two units of alcohol is unlikely to cause problems, but binge drinking should be avoided. Stay well hydrated, especially in hot weather or after exercise, as dehydration can also lower blood pressure. If you experience chest pain during or after sexual activity, stop and seek urgent medical help, as this may indicate a heart problem [1][2]. Do not take a nitrate medicine (such as GTN spray) if you have used tadalafil in the past 48 hours, as this combination is dangerous [4].

Other Blood-Pressure Medicines and Tadalafil Interactions

Valsartan is just one of many blood-pressure medicines, and it is helpful to understand how tadalafil interacts with other common classes. Alpha-blockers (such as doxazosin, tamsulosin, alfuzosin, and terazosin), often used for prostate symptoms or high blood pressure, carry a higher risk of low blood pressure when combined with tadalafil [4]. If you take an alpha-blocker, your prescriber will ensure you are stable on that medicine and will start tadalafil at the lowest dose, with careful monitoring [4].

Calcium-channel blockers (such as amlodipine, felodipine, or diltiazem) and ACE inhibitors (such as ramipril, lisinopril, or enalapril) can also add to the blood-pressure-lowering effect of tadalafil, but the interaction is generally manageable and does not prevent the combination [4]. Diuretics (water tablets such as bendroflumethiazide, furosemide, or indapamide) may also be used alongside tadalafil, again with prescriber assessment [4].

Beta-blockers (such as bisoprolol, atenolol, or metoprolol) do not have a significant direct interaction with tadalafil, but they are sometimes associated with erectile dysfunction as a side effect, so your prescriber may review whether your beta-blocker could be contributing to your ED [2]. If you take any combination of blood-pressure medicines (for example, valsartan plus amlodipine, or ramipril plus bendroflumethiazide), it is especially important to declare all of them during your consultation, as the cumulative effect on blood pressure must be considered [4]. Your prescriber will assess the overall risk and may adjust the tadalafil dose or recommend monitoring your blood pressure at home.

Medicines That Are Contraindicated with Tadalafil

Certain medicines must never be taken with tadalafil because the combination can cause a dangerous drop in blood pressure. These include nitrates (GTN spray, isosorbide mononitrate, isosorbide dinitrate), nicorandil (often used for angina), riociguat (for pulmonary hypertension), and recreational drugs known as 'poppers' (amyl or alkyl nitrites) [3][4]. Do not take tadalafil if you use any of these medicines or substances. You should also not take tadalafil together with another PDE5 inhibitor (such as sildenafil or vardenafil), as this increases the risk of side effects without improving effectiveness [3][4]. Always tell your prescriber about every medicine, supplement, and recreational substance you use.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 26 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 26 October 2026]
3. Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 26 October 2026]
4. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 26 October 2026]
5. Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 26 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.