Vardenafil and Propylthiouracil: Can You Take Them Together?

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Key takeaways

• No major interaction is reported between vardenafil and propylthiouracil in clinical practice
• Your prescriber reviews your thyroid condition and heart health before approving vardenafil
• Take each medicine as directed with no need to separate doses
• Seek urgent help for erections lasting over four hours or sudden vision or hearing loss
• Continue your thyroid treatment as prescribed and attend regular monitoring appointments

What Is Vardenafil and How Does It Work?

Vardenafil, also known by the brand name Levitra, is a prescription medicine used to treat erectile dysfunction in adult men [5]. It belongs to a group of medicines called PDE5 inhibitors, which work by relaxing the blood vessels in the penis, allowing increased blood flow when you are sexually aroused. This helps you to achieve and maintain an erection suitable for sexual activity.

Vardenafil is available in 5mg, 10mg, and 20mg tablets and is typically taken about 25 to 60 minutes before sexual activity [5]. The effect can last for several hours, but you should not take more than one dose in a 24-hour period. It's important to remember that vardenafil will only work when you are sexually stimulated—it does not cause an automatic erection.

Like all PDE5 inhibitors, vardenafil is only available on prescription in the UK. At Cured Pharmacy, a UK-registered prescriber will review your online consultation to ensure vardenafil is safe and suitable for you, taking into account your medical history and any other medicines you are taking.

What Is Propylthiouracil and Why Is It Prescribed?

Propylthiouracil (often abbreviated as PTU) is a prescription medicine used to treat hyperthyroidism, a condition where the thyroid gland produces too much thyroid hormone. This can cause symptoms such as a rapid heartbeat, weight loss, anxiety, tremor, and heat intolerance. Propylthiouracil works by reducing the amount of thyroid hormone your body produces, helping to bring hormone levels back to normal.

Propylthiouracil is particularly used in certain situations, such as during the first trimester of pregnancy or in patients who cannot tolerate other anti-thyroid medicines like carbimazole. It is usually taken two or three times a day, and regular blood tests are needed to monitor your thyroid function and adjust the dose if necessary.

Managing thyroid conditions is important for overall health. Untreated hyperthyroidism can affect your heart, bones, and other organs. If you have been prescribed propylthiouracil, it's essential to take it exactly as directed by your doctor and attend all follow-up appointments. Always inform any healthcare professional, including pharmacists and prescribers, that you are taking propylthiouracil when seeking treatment for other conditions.

Thyroid Health and Erectile Function

Thyroid disorders, including both hyperthyroidism and hypothyroidism (underactive thyroid), can sometimes contribute to erectile dysfunction. Thyroid hormones play a role in regulating metabolism, energy levels, and sexual function. If your thyroid condition is not well controlled, it may affect your ability to achieve or maintain an erection. Treating the underlying thyroid problem with medicines like propylthiouracil can sometimes improve ED symptoms as your hormone levels stabilise.

At a glance

Is There an Interaction Between Vardenafil and Propylthiouracil?

No major direct interaction between vardenafil and propylthiouracil is commonly reported in clinical practice or standard drug interaction databases. These two medicines work through different mechanisms in the body: vardenafil acts on blood vessels in the penis to improve erectile function, while propylthiouracil reduces thyroid hormone production. They do not interfere with each other's metabolism or effects in a clinically significant way.

However, this does not mean you can simply take them together without medical oversight. When you request vardenafil through Cured Pharmacy, a UK-registered prescriber will review your full medical history, including your thyroid condition and all current medications, to ensure the combination is safe for you. Certain medical conditions or other medicines you may be taking could affect whether vardenafil is suitable.

It's also worth noting that hyperthyroidism itself can sometimes cause cardiovascular symptoms such as a rapid or irregular heartbeat. Your prescriber will check that your thyroid condition is stable and that your heart is healthy enough for sexual activity before prescribing vardenafil. If you have any concerns about taking vardenafil alongside propylthiouracil, discuss them during your consultation or speak to your GP.

What Your Prescriber Checks Before Approving Vardenafil

When you complete an online consultation for vardenafil at Cured Pharmacy, a UK-registered prescriber will carefully review your answers to ensure the medicine is safe for you. They will check for any medical conditions or medicines that could make vardenafil unsuitable or require dose adjustments. This includes checking your heart health, blood pressure, and any history of stroke, liver or kidney problems, or eye conditions.

Your prescriber will also review all your current medicines, including propylthiouracil, to identify any potential interactions. While propylthiouracil itself does not interact with vardenafil, other medicines you may be taking could. For example, certain blood pressure medicines, particularly alpha-blockers, can interact with vardenafil and increase the risk of dizziness or low blood pressure. Some medicines that affect liver enzymes, such as potent CYP3A4 inhibitors, can raise vardenafil levels in the blood and may require dose adjustments or make vardenafil unsuitable [5].

It's crucial to list all your medicines accurately in your consultation, including prescription medicines, over-the-counter treatments, herbal remedies, and supplements. Never take vardenafil if you are using nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, or recreational drugs known as 'poppers', as the combination can cause a dangerous drop in blood pressure. Do not take vardenafil together with another PDE5 inhibitor.

Cardiovascular Considerations with Thyroid Conditions

Hyperthyroidism can put extra strain on your heart, sometimes causing symptoms such as palpitations, atrial fibrillation, or high blood pressure. Before prescribing vardenafil, your prescriber will want to know that your thyroid condition is being managed and that your cardiovascular system is stable. Sexual activity itself requires a degree of physical exertion, so it's important that your heart is healthy enough for this. If you have any concerns about your heart health, mention them in your consultation.

Practical Advice for Taking Vardenafil with Propylthiouracil

If your prescriber approves vardenafil, you can take it alongside propylthiouracil without any special timing requirements. There is no need to separate the doses or take them at different times of day. Simply take each medicine as directed: propylthiouracil as prescribed by your doctor (usually two or three times daily), and vardenafil about 25 to 60 minutes before planned sexual activity [5].

Continue to take propylthiouracil exactly as your doctor has instructed, even on days when you plan to use vardenafil. Do not stop or change the dose of propylthiouracil without consulting your doctor, as this could affect your thyroid hormone levels and overall health. Similarly, follow the dosing instructions for vardenafil carefully: do not take more than one dose in 24 hours, and remember that sexual stimulation is needed for the medicine to work.

Avoid drinking large amounts of alcohol when using vardenafil, as alcohol can make erectile dysfunction worse and increase the risk of side effects such as dizziness or low blood pressure. Grapefruit juice can also raise vardenafil levels in the blood, so it's best to avoid it. If you experience any unusual symptoms or side effects while taking vardenafil and propylthiouracil together, contact your GP or pharmacist for advice.

Warning Signs and When to Seek Urgent Help

While vardenafil is generally well tolerated, there are some rare but serious side effects that require urgent medical attention. If you develop an erection that lasts longer than four hours (known as priapism), seek immediate help by going to A&E or calling 999. Priapism can damage the penis if not treated promptly. You should also seek urgent help if you experience sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing, which may be accompanied by ringing in the ears or dizziness.

If you develop chest pain during or after sexual activity, stop and seek medical help. Do not take nitrate medicines (such as GTN spray) to relieve chest pain if you have used vardenafil in the past 24 hours, as the combination can cause a dangerous drop in blood pressure. Instead, call 999 or go to A&E and tell the healthcare team that you have taken vardenafil.

If you notice symptoms that might suggest your thyroid condition is not well controlled—such as a very rapid or irregular heartbeat, severe tremor, chest pain, or feeling very unwell—contact your GP or endocrinologist promptly. While these symptoms are related to your thyroid rather than vardenafil, it's important to keep your thyroid condition stable to ensure your overall health and the safety of any ED treatment.

Common Side Effects of Vardenafil

Common side effects of vardenafil include headache, flushing (redness of the face), nasal congestion, indigestion, and dizziness [5]. These are usually mild and temporary. If side effects are troublesome or persistent, speak to your pharmacist or prescriber. Rarely, vardenafil can cause more serious side effects such as changes in vision or hearing, severe skin reactions, or prolonged erections. Always read the patient information leaflet that comes with your medicine and report any unexpected symptoms to a healthcare professional.

When to get urgent help

• Erection lasting longer than four hours (priapism) – go to A&E or call 999 immediately
• Sudden loss of vision in one or both eyes – seek urgent medical help
• Sudden decrease or loss of hearing, possibly with ringing in the ears or dizziness
• Chest pain during or after sexual activity – call 999 and tell them you have taken vardenafil
• Severe or rapid heartbeat, chest pain, or feeling very unwell (may indicate uncontrolled thyroid condition) – contact your GP or endocrinologist urgently

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

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