Vardenafil and Nitrates: Never Take Together

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What is vardenafil and how does it work?

Vardenafil is a prescription-only medicine used to treat erectile dysfunction (ED) in adult men. It belongs to a group of medicines called PDE5 inhibitors, which also includes sildenafil (Viagra), tadalafil (Cialis), and avanafil (Spedra). Vardenafil works by relaxing the blood vessels in the penis, allowing more blood to flow into the area when you are sexually aroused, which helps you get and keep an erection [5].

The medicine is usually taken about 25 to 60 minutes before sexual activity, and it comes in doses of 5mg, 10mg, and 20mg. The typical starting dose is 10mg, which your prescriber may adjust depending on how well it works and whether you experience any side effects. Vardenafil does not cause an erection on its own—you still need sexual stimulation for it to work [5].

Like all PDE5 inhibitors, vardenafil lowers blood pressure slightly as part of how it works. This effect is usually mild and not a problem for most men, but it becomes extremely dangerous when combined with certain other medicines that also lower blood pressure, particularly nitrates [5].

What are nitrates and why are they prescribed?

Nitrates are a group of medicines commonly prescribed to treat angina, which is chest pain caused by reduced blood flow to the heart muscle. They work by relaxing and widening blood vessels throughout the body, which reduces the workload on the heart and improves blood flow. This helps to relieve chest pain and prevent angina attacks [3].

Common nitrate medicines in the UK include glyceryl trinitrate (GTN) spray or tablets, isosorbide mononitrate (often taken once or twice daily), and isosorbide dinitrate. GTN spray is often used for quick relief during an angina attack, while the tablet forms are usually taken regularly to prevent attacks from happening [3].

Because nitrates lower blood pressure as their main action, combining them with vardenafil—which also lowers blood pressure—creates a compounding effect. The result can be a sudden, severe drop in blood pressure that the body cannot compensate for quickly enough, leading to serious medical emergencies [5].

Other nitrate-containing products to avoid

It's important to know that nitrates are not only found in prescription medicines. Amyl nitrite and alkyl nitrites, often sold as 'poppers' and used recreationally, also contain nitrates and are absolutely contraindicated with vardenafil. Taking vardenafil with poppers carries the same life-threatening risk of severe blood pressure drop [5]. Always tell your prescriber about any recreational substances you use, as this information is treated confidentially and is essential for your safety.

When to get urgent help

• Severe dizziness, fainting, or loss of consciousness after taking vardenafil
• Chest pain during or after sex—do not use nitrates if you have taken vardenafil; call 999
• Sudden blurred vision, confusion, or difficulty breathing after taking vardenafil
• Erection lasting more than 4 hours (priapism)—go to A&E immediately
• Rapid or irregular heartbeat with dizziness after taking vardenafil and any other medicine

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

Why vardenafil and nitrates are a dangerous combination

The interaction between vardenafil and nitrates is one of the most serious drug interactions in medicine. Both medicines cause blood vessels to relax and widen, which lowers blood pressure. When taken together, this effect is greatly amplified, and blood pressure can fall to dangerously low levels very quickly [5].

This sudden drop in blood pressure can cause dizziness, fainting, and loss of consciousness. More seriously, it can reduce blood flow to vital organs including the heart and brain, potentially triggering a heart attack or stroke. In some cases, the drop in blood pressure can be fatal. This is why vardenafil and nitrates are absolutely contraindicated—meaning they must never be used together under any circumstances [5].

The risk applies to all forms of nitrates, whether taken regularly (such as isosorbide mononitrate tablets) or used occasionally (such as GTN spray for angina attacks). Even if you only use your GTN spray rarely, you still cannot safely take vardenafil. The interaction can occur whether the nitrate is taken before, during, or after vardenafil, so there is no safe time gap between the two medicines [5].

What your prescriber checks before prescribing vardenafil

Before vardenafil can be prescribed, a UK-registered prescriber must review your full medical history and current medicines. This is a legal requirement and a vital safety step. The prescriber will specifically ask whether you take any nitrate medicines, have angina, or have any heart conditions that might require nitrate treatment [5].

You will be asked to list all your current medicines, including those prescribed by your GP, bought over the counter, herbal remedies, and any recreational substances. It is essential to answer these questions honestly and completely. If you take nitrates or any other contraindicated medicine, the prescriber will not be able to approve vardenafil, but they can discuss alternative treatments for erectile dysfunction [2].

The prescriber will also check for other conditions that make vardenafil unsuitable, such as recent heart attack or stroke, very low blood pressure, severe heart failure, or certain eye conditions. They will review any other medicines you take that might interact with vardenafil, such as alpha-blockers for prostate problems or certain antifungal and antiviral medicines [5]. At Cured Pharmacy, every order requires completion of an online consultation that is reviewed by a UK prescriber before any medicine is dispensed.

Medicines related to nitrates that also interact

Nicorandil is another medicine used for angina that works partly like a nitrate. It is also absolutely contraindicated with vardenafil for the same reason—the combination can cause a dangerous drop in blood pressure [5]. Riociguat, a medicine used for pulmonary hypertension, is similarly contraindicated with all PDE5 inhibitors including vardenafil [3]. Always declare every medicine you take, even if you are not sure whether it interacts.

At a glance

Safe alternatives if you take nitrates

If you take nitrates for angina or any other heart condition, oral PDE5 inhibitors like vardenafil, sildenafil, tadalafil, and avanafil are not safe options for you. However, erectile dysfunction can still be treated effectively using different approaches that do not interact with nitrates [2].

One option is alprostadil, which works in a completely different way to PDE5 inhibitors. Alprostadil is available as a cream (Vitaros) applied inside the tip of the penis or as an injection (Caverject) into the side of the penis. Because alprostadil works locally rather than affecting blood vessels throughout the body, it does not interact with nitrates and can be used safely in men taking these medicines [7].

Vacuum erection devices are another non-drug option. These are mechanical pumps that draw blood into the penis to create an erection, which is then maintained using a constriction ring. They are safe to use with any heart medicine and can be effective for many men [2]. Your GP or a specialist can discuss which option is most suitable for you. It is also important to address the underlying causes of ED, such as diabetes, high blood pressure, or lifestyle factors, as treating these can improve erectile function [1].

What to do if you've accidentally combined vardenafil and nitrates

If you have taken vardenafil and then experience chest pain, do not use your GTN spray or any other nitrate medicine. Similarly, if you have taken vardenafil within the last 24 hours, you must not use nitrates. Instead, call 999 immediately and tell the paramedics that you have taken vardenafil, as this will guide their treatment decisions [5].

If you have accidentally taken both vardenafil and a nitrate medicine together, seek emergency medical help straight away, even if you feel well. Call 999 or go to your nearest A&E department. Tell the medical team exactly what you have taken and when. Symptoms of a dangerous blood pressure drop include severe dizziness, fainting, blurred vision, confusion, rapid or irregular heartbeat, chest pain, or difficulty breathing [5].

Do not wait to see if symptoms develop—the interaction can be life-threatening and requires immediate medical assessment. Medical professionals will not judge you; they need accurate information to provide the right treatment. If you are unsure whether a medicine you have taken is a nitrate, seek medical advice anyway. It is always better to be cautious when it comes to this serious interaction [5].

Informing healthcare professionals

Always carry a list of your current medicines, including vardenafil if you have been prescribed it. If you need emergency medical treatment for any reason, inform doctors and paramedics that you take vardenafil, as this affects which medicines they can safely give you. Similarly, if you are prescribed a new medicine for your heart or blood pressure, remind your doctor that you take vardenafil so they can check for interactions [5].

In summary

• Vardenafil and nitrates must never be taken together due to risk of life-threatening blood pressure drop
• All nitrate medicines are contraindicated, including GTN spray, isosorbide, nicorandil, and poppers
• If you take nitrates, safe ED treatment alternatives include alprostadil or vacuum devices
• Always tell your prescriber about every medicine you take, including occasional or emergency medicines
• If you take vardenafil and get chest pain, do not use nitrates—call 999 immediately

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