Vardenafil and Sitagliptin: Can You Take Them Together?

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Key takeaways

• No major direct interaction between vardenafil and sitagliptin is commonly reported
• Your prescriber reviews all medicines and medical history before approving vardenafil
• Never take vardenafil with nitrates, nicorandil, riociguat, or poppers
• Good diabetes control can help improve erectile function over time
• Seek urgent help for erections lasting over 4 hours or sudden vision or hearing loss

What Is Vardenafil and How Does It Work?

Vardenafil is the generic name for Levitra, a prescription medicine used to treat erectile dysfunction (ED) in men [5]. 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 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 usually 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. Common side effects include headache, flushing, indigestion, and nasal congestion.

At Cured Pharmacy, vardenafil is available on prescription after an online consultation with a UK-registered prescriber. The consultation ensures the medicine is safe and suitable for you, taking into account your medical history and any other medicines you are taking.

What Is Sitagliptin and Why Is It Prescribed?

Sitagliptin is a medicine used to treat type 2 diabetes. It is sold under the brand name Januvia and is also available in combination tablets such as Janumet (sitagliptin with metformin). Sitagliptin belongs to a class of medicines called DPP-4 inhibitors (dipeptidyl peptidase-4 inhibitors), which help control blood sugar levels by increasing the release of insulin when blood sugar is high and reducing the amount of sugar made by the liver.

Sitagliptin is usually taken once a day, with or without food. It is often prescribed alongside other diabetes medicines and lifestyle changes such as diet and exercise. Common side effects can include headache, upper respiratory tract infections, and occasionally low blood sugar (hypoglycaemia), especially if taken with other diabetes medicines.

Managing diabetes well is important for overall health, including sexual health. High blood sugar over time can damage blood vessels and nerves, which may contribute to erectile dysfunction. Many men with diabetes find that controlling their blood sugar, staying active, and addressing ED with appropriate treatment can improve their quality of life.

The Link Between Diabetes and Erectile Dysfunction

Erectile dysfunction is more common in men with diabetes than in the general population [1]. High blood sugar levels can damage the small blood vessels and nerves that control erections. This is why good diabetes control, including medicines like sitagliptin, is an important part of managing ED. Treating the underlying diabetes does not always reverse ED, but it can help prevent further damage and improve overall health, making ED treatments more effective.

Do Vardenafil and Sitagliptin Interact With Each Other?

There is no well-documented direct pharmacological interaction between vardenafil and sitagliptin. They work through different mechanisms in the body: vardenafil acts on blood vessels in the penis, while sitagliptin affects insulin release and blood sugar control. This means that, in most cases, the two medicines can be taken together without one affecting how the other works.

However, it is important to remember that every person is different, and both medicines can have side effects. For example, vardenafil can cause a small drop in blood pressure, and some people with diabetes may also be taking other medicines (such as blood pressure tablets) that can add to this effect. Your prescriber will review your full medication list and medical history to make sure the combination is safe for you.

During your online consultation at Cured Pharmacy, you will be asked about all the medicines you are taking, including sitagliptin and any other diabetes or blood pressure treatments. This allows the prescriber to check for any potential interactions and to recommend the safest starting dose of vardenafil for your individual situation.

What Does Your Prescriber Check Before Approving Vardenafil?

Before prescribing vardenafil, your doctor or pharmacist prescriber will ask about your medical history, current medicines, and overall health [2]. This is to make sure vardenafil is safe for you and to identify any medicines or conditions that could cause problems. Key checks include whether you are taking nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, or recreational drugs called 'poppers', as these must never be taken with vardenafil due to the risk of a dangerous drop in blood pressure.

Your prescriber will also ask about alpha-blockers (medicines for prostate or blood pressure problems, such as tamsulosin or doxazosin), as these can interact with vardenafil and increase the risk of dizziness or fainting. If you are on an alpha-blocker, you may need to start on a lower dose of vardenafil and take extra care when standing up. Medicines that affect how the liver breaks down vardenafil—such as some antibiotics, antifungals, or HIV medicines—will also be reviewed, as they can increase vardenafil levels in the blood [5].

Because you have diabetes and are taking sitagliptin, your prescriber will also consider your overall cardiovascular health. Diabetes increases the risk of heart disease, and sexual activity itself puts some strain on the heart. Your prescriber will check that your heart and blood pressure are healthy enough for sex and that vardenafil is appropriate for you.

Medicines That Must Not Be Taken With Vardenafil

Do not take vardenafil if you are using nitrates (GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, or amyl/alkyl nitrites ('poppers'). Do not take vardenafil at the same time as another PDE5 inhibitor (such as sildenafil, tadalafil, or avanafil). Combining these medicines with vardenafil can cause a serious and potentially life-threatening drop in blood pressure [5]. Always tell your prescriber about every medicine you take, including over-the-counter and herbal products.

Practical Advice for Taking Vardenafil and Sitagliptin Together

If your prescriber approves vardenafil for you, continue taking sitagliptin exactly as prescribed by your diabetes doctor. Do not stop or change your diabetes medicine without medical advice, as this could affect your blood sugar control. Take vardenafil about 25 to 60 minutes before you plan to have sex, and remember that it works only with sexual stimulation—it will not cause an automatic erection [5].

Avoid drinking large amounts of alcohol when taking vardenafil, as alcohol can make it harder to get an erection and can add to the blood-pressure-lowering effect of the medicine, increasing the risk of dizziness. Grapefruit juice can also increase the levels of vardenafil in your blood, so it is best to avoid it. If you experience dizziness or light-headedness, sit or lie down until you feel better, and avoid driving or operating machinery.

Keep an eye on your blood sugar levels as usual, especially if you are adjusting to new diabetes medicines or if your routine changes. Good diabetes control, a healthy diet, regular exercise, and not smoking can all help improve erectile function over time. If vardenafil does not work well for you, speak to your prescriber—there are other ED treatments available, and sometimes a different dose or a different PDE5 inhibitor may be more suitable.

When to Seek Medical Help and Warning Signs to Watch For

Most men tolerate vardenafil well, but it is important to know the warning signs that need urgent medical attention. If you develop an erection that lasts longer than four hours (called priapism), go to A&E immediately, as this can cause permanent damage if not treated quickly. Sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing (sometimes with ringing in the ears or dizziness), are rare but serious side effects—stop taking vardenafil and seek medical help straight away [5].

If you experience chest pain, severe dizziness, or fainting during or after sex, stop and seek medical help. Do not take nitrates (such as GTN spray) to relieve chest pain if you have taken vardenafil in the past 24 hours, as this combination can be dangerous. If you have any concerns about side effects or if vardenafil does not seem to be working, contact your prescriber or GP for advice.

Remember that erectile dysfunction can sometimes be an early warning sign of heart disease or poorly controlled diabetes [1]. If you have not seen your GP about your ED or diabetes recently, it is a good idea to book a check-up. Managing your overall health—including blood sugar, blood pressure, cholesterol, and weight—can make a big difference to both your general wellbeing and your sexual health.

How Cured Pharmacy Can Help

Cured Pharmacy is a GPhC-registered online pharmacy offering discreet, convenient access to ED treatments after a consultation with a UK-registered prescriber. You can complete a short online questionnaire, and a prescriber will review your answers and medical history to decide whether vardenafil or another ED medicine is safe and suitable for you. If approved, your medicine is dispensed by our pharmacy and delivered discreetly to your door. We are here to support you with clear information, professional advice, and genuine care.

When to get urgent help

• Erection lasting longer than 4 hours (priapism) — go to A&E immediately
• Sudden loss of vision in one or both eyes — stop vardenafil and seek urgent medical help
• Sudden decrease or loss of hearing, sometimes with ringing or dizziness — seek medical help
• Chest pain during or after sex — stop activity and seek medical help; do not take nitrates if you have used vardenafil in the past 24 hours
• Severe dizziness, fainting, or signs of a serious allergic reaction (swelling of face, lips, or throat; difficulty breathing)

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