Vardenafil and Letrozole: Can You Take Them Together?

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At a glance

What is vardenafil and how does it work?

Vardenafil (generic Levitra) is a phosphodiesterase type 5 (PDE5) inhibitor licensed in the UK to treat erectile dysfunction [5]. It works by relaxing the blood vessels in the penis, allowing more blood to flow in when you are sexually aroused. This helps you get and keep an erection suitable for sexual activity.

Vardenafil is available in 5 mg, 10 mg, and 20 mg tablets. You take it about 25 to 60 minutes before sexual activity, and it works only when you are sexually stimulated [5]. The effects can last for several hours, but you should not take more than one dose in 24 hours.

Like all PDE5 inhibitors, vardenafil requires a prescription in the UK. At Cured Pharmacy, a UK-registered prescriber reviews your online consultation to check that vardenafil is suitable and safe for you, taking into account your medical history and any other medicines you are taking.

What is letrozole and why is it prescribed?

Letrozole is an aromatase inhibitor, a type of medicine that reduces the production of oestrogen in the body. It is most commonly prescribed to treat hormone-receptor-positive breast cancer in postmenopausal women. By lowering oestrogen levels, letrozole can slow or stop the growth of certain types of breast cancer cells that need oestrogen to grow.

In men, letrozole is sometimes used off-label (outside its licensed indication) to treat conditions such as low testosterone or gynaecomastia (breast tissue enlargement), though this is less common. Letrozole does not directly treat erectile dysfunction, and it is not a substitute for ED medicines like vardenafil.

Letrozole is a prescription-only medicine and is usually taken as a daily tablet. Because it affects hormone levels, it requires careful monitoring by a doctor, especially when used alongside other medicines.

How letrozole affects the body

Letrozole works by blocking the enzyme aromatase, which converts androgens (male hormones) into oestrogen. This leads to lower oestrogen levels in the blood. In men, this can sometimes result in a compensatory increase in testosterone, which is why it may be prescribed off-label for certain hormonal imbalances. However, the effects on sexual function are not the same as those of ED medicines, and letrozole does not directly improve erections.

Do vardenafil and letrozole interact with each other?

There is no commonly reported major interaction between vardenafil and letrozole. These two medicines work through different mechanisms in the body: vardenafil acts on blood vessels in the penis to improve blood flow, while letrozole reduces oestrogen production by blocking an enzyme involved in hormone synthesis. They are not known to interfere with each other's effectiveness or safety in a clinically significant way.

However, it is important to remember that every person's medical situation is unique. When you complete an online consultation at Cured Pharmacy, the UK-registered prescriber reviews all your current medicines, including letrozole, to check for any potential interactions or contraindications. This ensures that vardenafil is safe and appropriate for you.

You should never assume that a combination is safe without professional review. Always declare every medicine you are taking, including prescription medicines, over-the-counter products, and supplements, during your consultation. This allows the prescriber to make an informed decision about your treatment.

What you need to know

• Vardenafil treats erectile dysfunction; letrozole is a hormone treatment, most often for breast cancer.
• No commonly reported major interaction between vardenafil and letrozole.
• Always declare all medicines during your consultation for a safe prescribing decision.
• Never take vardenafil with nitrates, nicorandil, riociguat, or poppers.
• See your GP if you have new ED, as it can signal heart disease or diabetes.

What does your prescriber check before prescribing vardenafil and letrozole?

When you request vardenafil, the prescriber will ask about your full medical history, including any heart conditions, blood pressure problems, liver or kidney disease, and any medicines you are currently taking. If you are taking letrozole, the prescriber will note this and check that there are no contraindications or interactions that could affect your safety.

The prescriber will also check that you are not taking any medicines that must never be used with vardenafil. These include nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, and amyl or alkyl nitrites (poppers). Combining vardenafil with any of these can cause a dangerous drop in blood pressure [5]. You must not take vardenafil with another PDE5 inhibitor at the same time.

If you are taking alpha-blockers (such as doxazosin or tamsulosin) or potent CYP3A4 inhibitors (such as ritonavir, ketoconazole, or clarithromycin), the prescriber will adjust your dose or advise whether vardenafil is suitable. Vardenafil is contraindicated or should be avoided with potent CYP3A4 inhibitors, as these can significantly raise vardenafil levels in the blood [5].

Why full disclosure matters

Declaring all your medicines, including letrozole, helps the prescriber identify any potential risks and tailor your treatment to your individual needs. Even if no major interaction is expected, the prescriber may still want to monitor your response or adjust your dose based on your overall health and treatment goals. Never stop or change a prescribed medicine without advice from your doctor or pharmacist.

Practical advice for taking vardenafil and letrozole together

If your prescriber confirms that vardenafil is suitable for you while you are taking letrozole, follow the dosing instructions carefully. Take vardenafil about 25 to 60 minutes before sexual activity, and do not take more than one dose in 24 hours [5]. Vardenafil works only when you are sexually aroused, so it will not cause an erection on its own.

Continue taking letrozole exactly as your doctor has prescribed. Do not stop or change your letrozole dose because you are starting vardenafil. If you have any questions about your hormone treatment or how it might affect your sexual health, speak to the doctor who prescribed letrozole.

Be aware of common side effects of vardenafil, which can include headache, flushing, indigestion, nasal congestion, and dizziness [5]. If you experience chest pain during sex, stop and seek urgent medical help. If you have an erection lasting more than four hours (priapism), or sudden loss of vision or hearing, go to A&E immediately.

Avoid drinking large amounts of alcohol when taking vardenafil, as this can make erectile dysfunction worse and increase the risk of dizziness or low blood pressure. Grapefruit juice can raise vardenafil levels in the blood, so it is best to avoid it.

When to get urgent help

• Erection lasting more than 4 hours (priapism) – go to A&E immediately
• Sudden loss of vision or hearing – seek urgent medical help
• Chest pain during or after sex – stop activity and call 999
• Severe dizziness or fainting after taking vardenafil – seek same-day medical advice

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

When to see your GP about vardenafil and letrozole

If you are experiencing new or worsening erectile dysfunction, it is important to see your GP. ED can be an early sign of underlying health conditions such as heart disease, diabetes, or high blood pressure [1]. Your GP can carry out tests, review your medicines, and refer you to a specialist if needed.

If you are taking letrozole for a medical condition and have concerns about how it might be affecting your sexual health or testosterone levels, discuss this with the doctor who prescribed it. They can review your hormone levels and consider whether any adjustments to your treatment are needed.

If you develop any new symptoms or side effects after starting vardenafil, or if vardenafil does not work as expected, contact your prescriber or GP. They can review your treatment and consider alternative options. At Cured Pharmacy, you can message the clinical team at any time if you have questions or concerns about your ED treatment.

Other ED treatment options

If vardenafil is not suitable or does not work well for you, other PDE5 inhibitors are available, including sildenafil (Viagra), tadalafil (Cialis), and avanafil (Spedra) [3][4][6]. Each has a slightly different onset and duration of action, and your prescriber can help you choose the best option. Non-oral treatments, such as alprostadil cream or injection, are also available for men who cannot use PDE5 inhibitors [7].

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