Vardenafil and Clonidine: Can They Be Taken Together?

Takes less than 2 minutes to complete 100% online

At a glance

What Is Vardenafil and How Does It Work?

Vardenafil (the active ingredient in 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 increased blood flow when you are sexually aroused. This helps you achieve and maintain an erection suitable for sexual activity [5].

Vardenafil is available in 5mg, 10mg, and 20mg tablets and is usually taken about 25 to 60 minutes before sexual activity [5]. The medicine only works when you are sexually stimulated—it does not cause an automatic erection. Effects can last for several hours, but you should not take more than one dose in 24 hours [5].

Like all PDE5 inhibitors, vardenafil can lower blood pressure slightly because it widens blood vessels throughout the body, not just in the penis [5]. This blood-pressure-lowering effect is usually mild, but it becomes important when vardenafil is combined with other medicines that also affect blood pressure, such as clonidine.

What Is Clonidine and Why Is It Prescribed?

Clonidine is a medicine primarily used to treat high blood pressure (hypertension). It works by stimulating certain receptors in the brain that reduce the signals sent to blood vessels, causing them to relax and widen. This lowers blood pressure and reduces the workload on the heart.

Clonidine is also sometimes prescribed for other conditions, including menopausal hot flushes, attention deficit hyperactivity disorder (ADHD), and certain pain conditions. It is usually taken two or three times a day, and the dose is carefully adjusted by your doctor to control your blood pressure without causing it to drop too low.

Because clonidine lowers blood pressure, combining it with other medicines that have the same effect—such as vardenafil—requires careful consideration. Your prescriber needs to ensure that the combination will not cause your blood pressure to fall to unsafe levels, leading to dizziness, fainting, or other complications.

How Clonidine Affects Blood Pressure

Clonidine reduces blood pressure by acting on the central nervous system. It decreases the release of noradrenaline, a chemical that normally causes blood vessels to tighten. With less noradrenaline, blood vessels remain more relaxed, and blood pressure stays lower. This effect is beneficial for managing hypertension but means that any additional blood-pressure-lowering medicine must be used cautiously.

Can Vardenafil and Clonidine Be Taken Together?

Yes, vardenafil and clonidine can usually be taken together, but only under the supervision of a prescriber who has reviewed your full medical history and current medicines. There is no absolute contraindication (a strict 'do not take together' rule) between vardenafil and clonidine, unlike the dangerous combination of vardenafil with nitrates, nicorandil, or riociguat [5].

However, both medicines can lower blood pressure, so there is a risk that taking them together may cause an additive effect—meaning your blood pressure could drop more than intended [5]. This can lead to symptoms such as dizziness, light-headedness, fainting, or a rapid heartbeat, particularly when you stand up quickly.

Your prescriber will assess whether it is safe for you to use vardenafil while taking clonidine. They will consider your current blood pressure control, the dose of clonidine you are taking, any other blood-pressure medicines you use, and your overall cardiovascular health. If vardenafil is prescribed, you may be started on a lower dose to minimise the risk of low blood pressure [5].

What you need to know

• Vardenafil and clonidine can usually be taken together under prescriber supervision
• Both medicines can lower blood pressure, so an additive effect is possible
• Your prescriber will review your blood pressure control and may start you on a lower vardenafil dose
• Never take vardenafil with nitrates, nicorandil, or riociguat—this is strictly contraindicated
• Watch for dizziness or fainting and seek urgent help for chest pain or prolonged erection

How Do Vardenafil and Clonidine Interact?

The interaction between vardenafil and clonidine is pharmacodynamic, meaning it is based on how the two medicines affect the body rather than how they are processed chemically. Both medicines can cause blood vessels to widen (vasodilation), which lowers blood pressure [5].

Clonidine reduces blood pressure by acting on the brain to decrease the signals that tighten blood vessels. Vardenafil, on the other hand, works mainly in the penis but also has a mild effect on blood vessels elsewhere in the body. When taken together, these effects can add up, potentially causing a greater drop in blood pressure than either medicine would cause alone.

This additive effect does not mean the combination is unsafe for everyone—many men take vardenafil successfully while on clonidine or other blood-pressure medicines. The key is careful prescribing: your doctor or pharmacist prescriber will check that your blood pressure is stable, that you are not at high risk of fainting or falls, and that the dose of vardenafil is appropriate for your situation [5].

What Your Prescriber Will Check

During your online consultation at Cured Pharmacy, the prescriber will ask about your current blood pressure, how well controlled it is, and whether you have experienced dizziness or fainting. They will review all your medicines, including clonidine, and check for any other conditions that might make vardenafil unsuitable. If vardenafil is appropriate, they may recommend starting with the lowest effective dose and monitoring how you respond.

Practical Advice for Taking Vardenafil and Clonidine

If your prescriber approves the combination of vardenafil and clonidine, follow these practical steps to use both medicines safely. Take vardenafil exactly as prescribed—usually about 25 to 60 minutes before sexual activity—and do not exceed one dose in 24 hours [5]. Continue taking clonidine as directed by your doctor; do not stop or change the dose without medical advice, as stopping clonidine suddenly can cause a dangerous rebound rise in blood pressure.

Be cautious when standing up, especially after taking vardenafil, as the combination may make you feel dizzy or light-headed. Sit on the edge of the bed for a moment before standing, and avoid sudden movements. Limit alcohol intake, as heavy drinking can worsen erectile dysfunction and add to the blood-pressure-lowering effect, increasing the risk of dizziness [5].

Monitor how you feel after taking vardenafil. If you experience severe dizziness, fainting, chest pain during sex, or an erection lasting more than four hours, seek urgent medical help. Report any new or worsening symptoms to your GP or pharmacist. Always declare clonidine and any other medicines during your consultation, as this allows the prescriber to tailor your treatment safely.

When to get urgent help

• Chest pain or discomfort during or after sexual activity
• An erection lasting more than four hours (priapism)
• Sudden loss of vision in one or both eyes
• Severe dizziness, fainting, or feeling like you might pass out
• Sudden decrease or loss of hearing, possibly with ringing in the ears

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

Other Medicines and Vardenafil: What Else to Watch For

In addition to clonidine, several other types of medicine can interact with vardenafil and require careful prescriber review. Never take vardenafil with nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, or recreational drugs known as 'poppers' (amyl or alkyl nitrites)—this combination can cause a dangerous drop in blood pressure and is strictly contraindicated [5].

Alpha-blockers (such as doxazosin, tamsulosin, or alfuzosin), used for prostate symptoms or high blood pressure, also carry a risk of low blood pressure when combined with vardenafil. If you take an alpha-blocker, you should be stable on that medicine before starting vardenafil, and your prescriber will usually recommend the lowest dose of vardenafil [5].

Potent CYP3A4 inhibitors—medicines such as ritonavir, cobicistat, ketoconazole, itraconazole, or clarithromycin—can raise vardenafil levels in the blood, increasing the risk of side effects. Vardenafil is often contraindicated or requires dose adjustment with these medicines, so your prescriber will check your full medication list carefully [5]. CYP3A4 inducers (such as rifampicin, carbamazepine, phenytoin, or St John's wort) can reduce vardenafil's effectiveness. Grapefruit juice may also raise vardenafil levels and should be avoided [5].

Declaring All Your Medicines

During your online consultation, you will be asked to list every medicine you take, including over-the-counter products, herbal remedies, and supplements. This is essential for safe prescribing. If you are unsure whether a medicine interacts with vardenafil, declare it anyway—the prescriber will review it and advise you. Never stop or change a prescribed medicine without consulting your doctor or pharmacist.

Choose your treatment

Select from our recommended UK-licensed medications.

Answer quick questions

Select safe UK treatments. Quick answers.

Get it delivered fast

We will deliver direct to you as quickly as tomorrow.