Vardenafil and Methocarbamol: Can They Be Taken Together?

Takes less than 2 minutes to complete 100% online

Key takeaways

• No major interaction is commonly reported between vardenafil and methocarbamol
• Both medicines can cause dizziness; stand up slowly and limit alcohol
• Always declare every medicine during your consultation so the prescriber can check safety
• Never take vardenafil with nitrates, nicorandil, riociguat, or poppers
• Contact your GP if you experience severe dizziness, fainting, or any concerning symptoms

What is vardenafil and how does it work?

Vardenafil is a prescription medicine used to treat erectile dysfunction (ED) in adult men [5]. It belongs to a group of medicines called phosphodiesterase type 5 (PDE5) inhibitors, which also includes sildenafil (Viagra) and tadalafil (Cialis). Vardenafil works by relaxing the blood vessels in the penis, allowing more blood to flow in when you are sexually aroused [5]. This helps you achieve and maintain an erection suitable for sexual activity.

Vardenafil is available in 5 mg, 10 mg, and 20 mg 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. You should take vardenafil no more than once a day. Common side effects include headache, flushing, nasal congestion, and indigestion [5]. Vardenafil is not suitable for everyone, particularly men taking nitrates, nicorandil, riociguat, or those with certain heart conditions.

What is methocarbamol and why is it prescribed?

Methocarbamol is a muscle relaxant medicine used to relieve painful muscle spasms and stiffness. It is often prescribed for short-term relief of acute musculoskeletal conditions, such as back pain, neck pain, or muscle strains. Methocarbamol works on the central nervous system to reduce muscle tension and discomfort, though the exact mechanism is not fully understood. It does not directly relax muscles but appears to have a general sedative effect that helps reduce muscle spasm.

Methocarbamol is usually taken as tablets, typically 1500 mg four times a day initially, then reduced as symptoms improve. Common side effects include drowsiness, dizziness, nausea, and headache. Because it can cause drowsiness, you should not drive or operate machinery until you know how it affects you. Methocarbamol may also interact with alcohol and other medicines that cause sedation, increasing the risk of drowsiness and dizziness.

How methocarbamol affects the body

Methocarbamol acts on the central nervous system rather than directly on muscle tissue. It may reduce nerve signals that cause muscles to contract involuntarily. Because it has sedative properties, it can make you feel sleepy or less alert, particularly when you first start taking it or if the dose is increased. This sedative effect is why methocarbamol is usually prescribed for short periods only, and why your doctor will review whether you still need it after a few weeks.

Can vardenafil and methocarbamol be taken together?

There is no well-documented major interaction between vardenafil and methocarbamol, and they are not known to directly interfere with each other's mechanism of action. Vardenafil works on blood vessels in the penis, while methocarbamol acts on the central nervous system to reduce muscle spasm. However, both medicines can cause dizziness and low blood pressure as side effects, so taking them together may increase the chance of feeling dizzy or lightheaded, particularly when you stand up quickly.

Your prescriber will review all your current medicines during your consultation to check for any potential interactions and ensure the combination is appropriate for you. It is important to declare every medicine you take, including over-the-counter products, herbal remedies, and supplements. Do not stop or change any prescribed medicine without speaking to your doctor or pharmacist first. If you experience unusual dizziness, fainting, or any other concerning symptoms, contact your GP or pharmacist for advice.

Why your prescriber needs to know about both medicines

Even when no major interaction is expected, your prescriber must know about every medicine you take to assess your overall risk. For example, if you also take blood pressure medicines, the combined effect of vardenafil and methocarbamol on blood pressure may be more significant. Your prescriber will also check that vardenafil is safe for you based on your heart health, as erectile dysfunction medicines are not suitable for men with certain cardiovascular conditions or those taking nitrates or nicorandil.

What your prescriber checks before approving vardenafil

Before vardenafil can be prescribed, a UK-registered prescriber will review your medical history and current medicines to ensure it is safe for you [5]. They will check whether you have any heart conditions, recent stroke or heart attack, very low blood pressure, or a history of sudden vision loss (non-arteritic anterior ischaemic optic neuropathy, or NAION). Vardenafil must never be taken with nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, or recreational drugs known as 'poppers' (amyl or alkyl nitrites), as this combination can cause a dangerous drop in blood pressure [5].

Your prescriber will also ask about other medicines that may interact with vardenafil. Alpha-blockers (such as tamsulosin or doxazosin, used for prostate or blood pressure problems) can increase the risk of low blood pressure and dizziness when taken with vardenafil; if you take an alpha-blocker, you should be stable on it and start vardenafil at the lowest dose [5]. Potent CYP3A4 inhibitors (such as ritonavir, ketoconazole, itraconazole, or clarithromycin) can raise vardenafil levels in the blood, and vardenafil is usually avoided or contraindicated with these medicines [5]. Your prescriber will also consider whether methocarbamol or any other medicine you take might add to side effects such as dizziness.

Practical advice for taking vardenafil and methocarbamol safely

If your prescriber approves the use of vardenafil alongside methocarbamol, follow these practical steps to minimise side effects. Take each medicine exactly as prescribed, at the dose and frequency your doctor has recommended. Vardenafil should be taken about 25 to 60 minutes before sexual activity, and no more than once a day [5]. Methocarbamol is usually taken at regular intervals throughout the day; do not take extra doses to 'catch up' if you miss one.

Because both medicines can cause dizziness, stand up slowly from sitting or lying down, especially in the first few days of treatment or if your dose changes. Avoid drinking large amounts of alcohol, as this can worsen dizziness and make erectile dysfunction worse. Do not drive or use machinery if you feel drowsy or dizzy. If you experience an erection lasting more than four hours, sudden loss of vision or hearing, or chest pain during sex, seek urgent medical help. Keep all your medicines in their original packaging, store them safely away from children, and check the expiry dates regularly.

When to contact your GP or pharmacist

Contact your GP or pharmacist if you develop new or worsening dizziness, fainting, severe headache, or any side effect that concerns you. If you are prescribed a new medicine by another doctor or buy an over-the-counter product, check with your pharmacist whether it is safe to take with vardenafil and methocarbamol. Never share your medicines with others, even if they have similar symptoms, as what is safe for you may not be safe for someone else.

Other medicines and vardenafil: what you need to know

Vardenafil interacts with several other medicines, and some combinations are dangerous. Never take vardenafil with nitrates (GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, or another PDE5 inhibitor (such as sildenafil or tadalafil), as this can cause a life-threatening drop in blood pressure [3][4][5]. Do not use recreational drugs called 'poppers' (amyl or alkyl nitrites) if you take vardenafil, as they contain nitrates and the combination is extremely dangerous.

Alpha-blockers used for prostate problems or high blood pressure (doxazosin, tamsulosin, alfuzosin, terazosin, prazosin, silodosin, indoramin) can increase the risk of dizziness and low blood pressure when taken with vardenafil; your prescriber will start you on the lowest dose and ensure you are stable on the alpha-blocker first [5]. Potent CYP3A4 inhibitors, including some HIV medicines (ritonavir, cobicistat), antifungals (ketoconazole, itraconazole), and antibiotics (clarithromycin), can raise vardenafil levels and are usually avoided [5]. CYP3A4 inducers such as rifampicin, carbamazepine, phenytoin, and St John's wort may reduce vardenafil's effectiveness. Grapefruit juice can also raise vardenafil levels and should be avoided. Always declare every medicine, supplement, and herbal product during your consultation.

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 – call 999 and do not take more vardenafil
• Severe dizziness or fainting that does not improve – contact your GP or call 111

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