Can You Take Sildenafil and Valsartan Together?

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Key takeaways

• Sildenafil and valsartan can usually be taken together if your blood pressure is stable.
• Both medicines can lower blood pressure, so your prescriber checks your cardiovascular health first.
• Start on a lower sildenafil dose if needed and monitor for dizziness or light-headedness.
• Never stop valsartan without medical advice; uncontrolled BP can worsen erectile dysfunction.
• Nitrates, nicorandil, and riociguat are contraindicated with sildenafil—valsartan is not.

What is sildenafil and valsartan used for?

Sildenafil is a medicine used to treat erectile dysfunction (ED) in men [1]. 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're sexually aroused [3]. Sildenafil is the active ingredient in branded Viagra and is available in generic forms at 25 mg, 50 mg, and 100 mg strengths. It's typically taken about one hour before sexual activity and should not be used more than once a day [3].

Valsartan is an angiotensin receptor blocker (ARB) used to treat high blood pressure (hypertension) and heart failure [12]. It works by blocking the action of a hormone called angiotensin II, which normally causes blood vessels to narrow. By blocking this hormone, valsartan helps blood vessels relax and widen, which lowers blood pressure and reduces the workload on the heart. Many people take valsartan long-term to keep their blood pressure under control and reduce the risk of heart attacks and strokes.

Both medicines affect blood vessels and blood pressure, which is why it's important to understand how they work together. While they're not contraindicated (forbidden to use together), the combination requires careful assessment by a prescriber to ensure it's safe for you.

How do sildenafil and valsartan interact?

Sildenafil and valsartan can both lower blood pressure, so when taken together, there's a potential for an additive effect—meaning your blood pressure might drop more than it would with either medicine alone [3]. This interaction is usually manageable, but it's the reason why your prescriber needs to review your current blood pressure readings and overall cardiovascular health before approving sildenafil.

The mechanism is straightforward: valsartan lowers blood pressure by relaxing and widening blood vessels throughout your body, while sildenafil primarily affects blood vessels in the penis but also has a mild blood-pressure-lowering effect overall [3]. When both medicines are working at the same time, you might experience symptoms of low blood pressure such as dizziness, light-headedness, or feeling faint, especially when standing up quickly.

It's important to note that this interaction is very different from the dangerous interaction between sildenafil and nitrate medicines (such as GTN spray or isosorbide mononitrate). Nitrates and PDE5 inhibitors must never be taken together because the combination can cause a severe, life-threatening drop in blood pressure [3]. Valsartan does not carry this same risk, and many men take sildenafil safely alongside ARBs like valsartan once their prescriber has confirmed it's appropriate.

Is the combination safe?

For most men whose blood pressure is well controlled on valsartan, adding sildenafil is considered safe [2]. The key is that your blood pressure should be stable—not too high and not too low—before starting ED treatment. Your prescriber will check your recent blood pressure readings, ask about any symptoms of low blood pressure (such as dizziness or fainting), and review your overall heart health. If you have very low blood pressure or unstable cardiovascular disease, sildenafil may not be suitable [3].

At a glance

What does your prescriber check before prescribing sildenafil and valsartan together?

When you request sildenafil through Cured Pharmacy's online consultation, the UK-registered prescriber will ask detailed questions about your current medicines, including valsartan, and your cardiovascular health. They'll want to know your recent blood pressure readings, whether you've experienced any dizziness or fainting, and whether you have any history of heart disease, stroke, or other cardiovascular conditions [2].

The prescriber will also check that you're not taking any medicines that are contraindicated with sildenafil. These include nitrates (GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, and amyl or alkyl nitrites (poppers) [3]. If you're on any of these medicines, you cannot take sildenafil. The prescriber will also review any other blood-pressure medicines you're taking, as multiple antihypertensives can add to the blood-pressure-lowering effect.

If your blood pressure is well controlled and you have no contraindications, the prescriber will usually approve sildenafil, often starting at a lower dose (such as 25 mg or 50 mg) to see how you respond [3]. You'll be advised to monitor for any symptoms of low blood pressure and to contact your GP or the pharmacy if you experience persistent dizziness, light-headedness, or fainting.

Practical advice for taking sildenafil with valsartan

If your prescriber approves sildenafil, take it exactly as directed—usually about one hour before sexual activity, with or without food [3]. Avoid taking sildenafil more than once in 24 hours. Continue taking your valsartan as prescribed by your GP; do not stop or change the dose without medical advice, as this could cause your blood pressure to rise.

Be aware of how you feel when you first start sildenafil. Some men notice mild dizziness or light-headedness, especially if they stand up quickly. This is usually temporary and improves as your body adjusts. If you feel dizzy, sit or lie down until it passes, and avoid driving or operating machinery until you know how the combination affects you. Drinking plenty of water and avoiding heavy alcohol can also help, as alcohol can add to the blood-pressure-lowering effect and make ED worse [1].

If you experience persistent or severe dizziness, fainting, chest pain during sex, or an erection lasting more than four hours, seek urgent medical help. These are rare but serious side effects that need immediate attention [3]. For routine concerns or questions about your treatment, contact Cured Pharmacy or your GP.

Can you adjust the dose?

Your prescriber may start you on a lower dose of sildenafil (such as 25 mg) if you're taking valsartan or other blood-pressure medicines, to minimise the risk of low blood pressure [3]. If the lower dose works well and you have no side effects, you can continue with it. If it's not effective enough, your prescriber may increase the dose to 50 mg or 100 mg, provided your blood pressure remains stable. Never adjust the dose yourself—always discuss any changes with your prescriber or pharmacist.

Other blood pressure medicines and sildenafil

Valsartan is one of several types of blood pressure medicines, and the advice for taking sildenafil varies slightly depending on which class of antihypertensive you're on. ARBs like valsartan, ACE inhibitors (such as ramipril or lisinopril), calcium channel blockers (such as amlodipine), and diuretics (such as bendroflumethiazide) can all be taken with sildenafil, but the prescriber must check your blood pressure control and overall cardiovascular health [2][3].

Alpha-blockers (such as doxazosin, tamsulosin, or alfuzosin, often used for prostate symptoms) carry a higher risk of low blood pressure when combined with sildenafil [3]. If you're on an alpha-blocker, you should be stable on that medicine first, and your prescriber will start you on the lowest dose of sildenafil. The two medicines should ideally be taken at different times of day to reduce the risk of dizziness.

If you're on multiple blood pressure medicines, it's especially important to declare all of them during your consultation. The prescriber will assess the cumulative effect and decide whether sildenafil is safe for you. Never stop taking your blood pressure medicines to make room for sildenafil—uncontrolled high blood pressure is a serious health risk and can itself contribute to erectile dysfunction [1][2].

Alternatives to sildenafil if you're on valsartan

If sildenafil is not suitable for you, or if you'd like to try a different PDE5 inhibitor, there are several alternatives. Tadalafil (Cialis) is another popular option that can be taken on-demand (10 mg or 20 mg at least 30 minutes before sex, with effects lasting up to 36 hours) or as a daily low dose (2.5 mg or 5 mg) [4]. Like sildenafil, tadalafil can lower blood pressure, so the same precautions apply when taking it with valsartan.

Vardenafil (Levitra) and avanafil (Spedra) are also PDE5 inhibitors with similar interactions [5][6]. All four medicines work in essentially the same way and require the same safety checks if you're on blood pressure treatment. The choice between them often comes down to how quickly they work, how long they last, and personal preference. Your prescriber can help you decide which is best for your situation.

At Cured Pharmacy, all PDE5 inhibitors are available on prescription after an online consultation reviewed by a UK prescriber. Prices start from £0.45 for generic sildenafil (£0.36 with first-order code Ednew). If oral medicines are not suitable, other options such as Vitaros (alprostadil cream) or Caverject (alprostadil injection) may be considered, though these also require a prescription and specialist assessment [7].

When to see your GP

If you're experiencing erectile dysfunction for the first time, it's a good idea to see your GP before starting treatment [1][2]. ED can be an early warning sign of cardiovascular disease or diabetes, and your GP can check for underlying causes and ensure your blood pressure and heart health are being properly managed. If you're already under a GP for valsartan and other conditions, keep them informed that you're using ED treatment, especially if you notice any new symptoms or side effects.

When to get urgent help

• Chest pain or discomfort during or after sex—call 999 and do not take nitrates
• An erection lasting more than 4 hours (priapism)—go to A&E immediately
• Sudden loss of vision or hearing—seek urgent medical attention
• Severe dizziness, fainting, or feeling very unwell—contact your GP or call 111
• Allergic reaction (rash, swelling, difficulty breathing)—call 999

Call 999 or go to A&E in an emergency, or contact NHS 111 for urgent advice.

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