Vardenafil and Mysimba: Can You Take Them Together?

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Vardenafil and Mysimba: Understanding the Interaction

Published: 2 November 2026

Many men wonder whether vardenafil and Mysimba can be taken together safely. Vardenafil (generic Levitra) is a prescription treatment for erectile dysfunction, while Mysimba is a prescription weight-loss medicine containing naltrexone and bupropion. No major direct interaction between these two medicines is commonly reported in standard references, but both can affect blood pressure and your prescriber will carefully review your full medical history and all current medicines during your consultation [5][12].

What is vardenafil and how does it work?

Vardenafil is a phosphodiesterase type 5 (PDE5) inhibitor licensed in the UK to treat erectile dysfunction [5]. It works by relaxing blood vessels in the penis, allowing increased blood flow when you are sexually aroused. Vardenafil is available in 5 mg, 10 mg, and 20 mg tablets and is usually taken about 25–60 minutes before sexual activity, with effects lasting for several hours [5].

Like all PDE5 inhibitors, vardenafil requires sexual stimulation to work—it will not cause an erection on its own [5]. The medicine is only supplied on prescription after an online or face-to-face consultation with a UK-registered prescriber, who will check your medical history, current medicines, and cardiovascular health to ensure it is safe and suitable for you.

Common side effects include headache, flushing, nasal congestion, and indigestion [5][12]. Vardenafil must never be taken with nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, poppers, or another PDE5 inhibitor, as the combination can cause a dangerous drop in blood pressure [5].

What is Mysimba and how does it work?

Mysimba is a prescription-only weight-loss medicine that combines two active ingredients: naltrexone (an opioid receptor antagonist) and bupropion (an antidepressant and smoking-cessation aid) [12]. It is licensed for weight management in adults with a body mass index (BMI) of 30 kg/m² or more, or 27 kg/m² or more if you have weight-related health conditions such as type 2 diabetes or high blood pressure.

Mysimba works on areas of the brain that control appetite and food cravings, helping you eat less and lose weight when combined with a reduced-calorie diet and increased physical activity [12]. The medicine is taken as tablets, with the dose gradually increased over the first few weeks to reduce the risk of side effects.

Common side effects of Mysimba include nausea, constipation, headache, vomiting, dizziness, dry mouth, and insomnia [12]. Bupropion, one of the active ingredients, can lower the seizure threshold (making fits more likely) and may raise blood pressure in some people, so your prescriber will monitor you closely. Mysimba is not suitable if you have uncontrolled high blood pressure, a history of seizures, an eating disorder, or if you are taking certain other medicines including monoamine oxidase inhibitors (MAOIs).

Can vardenafil and Mysimba be taken together?

No major direct interaction between vardenafil and Mysimba is commonly reported in standard UK references such as the British National Formulary [5][12]. This means that the two medicines do not directly interfere with each other's breakdown or action in the body in a way that is well-documented or clinically significant. However, this does not automatically mean the combination is suitable for everyone.

Both medicines can affect your cardiovascular system. Vardenafil lowers blood pressure slightly as part of its action on blood vessels [5], while bupropion (in Mysimba) can sometimes raise blood pressure or heart rate in certain individuals [12]. Your prescriber will assess your overall cardiovascular health, current blood pressure, and any other medicines you take to decide whether it is safe for you to use both treatments together.

It is essential that you declare all your current medicines—including Mysimba—when you request vardenafil through an online consultation. Your prescriber will review the combination in the context of your full medical history and may adjust doses, recommend monitoring, or suggest an alternative ED treatment if needed. Never start, stop, or change the dose of any prescribed medicine without professional advice.

What your prescriber will check

During your consultation, the prescriber will ask about your cardiovascular health, blood pressure, any history of seizures, mental health conditions, and all medicines you currently take [2][5]. They will check whether you are stable on Mysimba, whether your blood pressure is well controlled, and whether you have any conditions that make PDE5 inhibitors unsuitable (such as recent heart attack, unstable angina, or severe heart failure) [2][5].

If you are taking other medicines that lower blood pressure (such as antihypertensives for high blood pressure), the prescriber will consider the additive effect and may start you on a lower dose of vardenafil [5]. They will also ensure you are not taking any medicines that are absolutely contraindicated with vardenafil, such as nitrates, nicorandil, or riociguat [5].

Other medicines that interact with vardenafil and Mysimba

Vardenafil has several important interactions. It must never be taken with nitrates (GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, or amyl/alkyl nitrites (poppers), as the combination can cause a life-threatening drop in blood pressure [5]. Do not take vardenafil together with another PDE5 inhibitor (such as sildenafil or tadalafil) [5].

Alpha-blockers used for prostate symptoms (such as tamsulosin, doxazosin, alfuzosin) can add to the blood-pressure-lowering effect of vardenafil, increasing the risk of dizziness or fainting [5]. If you take an alpha-blocker, you should be stable on it before starting vardenafil, and your prescriber will usually recommend the lowest dose of vardenafil. Potent CYP3A4 inhibitors (such as ritonavir, cobicistat, ketoconazole, itraconazole, clarithromycin) can raise vardenafil levels significantly; vardenafil is often contraindicated or requires dose adjustment with these medicines—your prescriber must check the Summary of Product Characteristics [5][12].

Mysimba interacts with monoamine oxidase inhibitors (MAOIs), which must be stopped at least 14 days before starting Mysimba [12]. Bupropion can interact with medicines that lower the seizure threshold (such as antipsychotics, antidepressants, antimalarials, tramadol, theophylline) and with medicines metabolised by the liver enzyme CYP2D6 (such as some antidepressants, antipsychotics, beta-blockers, and tamoxifen) [12]. Always tell your prescriber about every medicine you take, including over-the-counter products and herbal remedies such as St John's wort.

Practical advice for taking vardenafil and Mysimba safely

If your prescriber approves the combination of vardenafil and Mysimba, take each medicine exactly as directed. Vardenafil is usually taken about 25–60 minutes before you plan to have sex, and you should not take more than one dose in 24 hours [5]. Mysimba is taken daily, with the dose built up gradually over several weeks as instructed by your prescriber [12].

Monitor your blood pressure regularly if you have been advised to do so, especially when starting or adjusting either medicine. Be aware of symptoms such as dizziness, light-headedness, or fainting, which can indicate low blood pressure. Avoid drinking large amounts of alcohol, as this can worsen erectile dysfunction, increase the risk of side effects from both medicines, and add to blood-pressure-lowering effects [1][5].

If you experience chest pain during or after sex, stop and seek urgent medical help—do not take a nitrate medicine (such as GTN spray) if you have used vardenafil in the past 24 hours, as this combination is dangerous [5]. Other warning signs that need urgent attention include an erection lasting more than four hours (priapism), sudden loss of vision or hearing, or seizures. Keep all your follow-up appointments and report any new symptoms or side effects to your prescriber or pharmacist promptly.

Lifestyle measures that support both treatments

Both erectile dysfunction and excess weight often share common underlying causes, including cardiovascular disease, type 2 diabetes, and low physical activity [1][2][10]. Losing weight through a healthy diet and regular exercise can improve erectile function, cardiovascular health, and overall wellbeing, making both Mysimba and vardenafil more effective [1][2].

Aim for at least 150 minutes of moderate-intensity aerobic activity each week, stop smoking, limit alcohol, and manage stress [1][2]. If you have not already done so, see your GP for a full health check, as erectile dysfunction can be an early warning sign of heart disease or diabetes [1][2]. Your GP can also review your blood pressure, cholesterol, and blood sugar, and adjust any other medicines you take to optimise your overall health.

When to seek further advice about vardenafil and Mysimba

Contact your prescriber or pharmacist if you experience new or worsening side effects after starting vardenafil or Mysimba, or if either medicine does not seem to be working as expected. If you develop symptoms such as persistent dizziness, fainting, chest pain, palpitations, severe headache, mood changes, or thoughts of self-harm, seek medical advice promptly [5][12].

If you are prescribed a new medicine by another healthcare professional (including your GP, a hospital specialist, or a dentist), always tell them you are taking both vardenafil and Mysimba so they can check for interactions. Similarly, if you buy any over-the-counter medicines, supplements, or herbal remedies, ask your pharmacist whether they are safe to take alongside your current treatments.

Erectile dysfunction that is new, worsening, or not responding to treatment should be discussed with your GP, as it may indicate an underlying health problem that needs investigation [1][2]. Your GP can arrange blood tests, review your cardiovascular risk, and refer you to a specialist if needed. At Cured Pharmacy, our UK-registered prescribers review every online consultation individually and will advise you if a face-to-face assessment or further tests are needed before prescribing.

How Cured Pharmacy can help

Cured Pharmacy is a GPhC-registered online pharmacy (GPhC 9012511) offering discreet, convenient access to erectile dysfunction treatments after a clinical consultation with a UK-registered prescriber. We stock a range of PDE5 inhibitors, including vardenafil, at transparent prices. Your consultation is reviewed individually, and our prescribers check all your current medicines—including Mysimba—to ensure any treatment is safe and suitable for you.

If you have questions about vardenafil and Mysimba or any other medicine interaction, our pharmacist-led team is here to help. You can contact us through the website or by phone for advice. Prescription medicines are only supplied after a consultation and prescriber approval, and we encourage you to see your GP for a full health review if you have not already done so.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 2 November 2026]
2. National Institute for Health and Care Excellence. (n.d.). Erectile dysfunction. Clinical Knowledge Summaries. https://cks.nice.org.uk/topics/erectile-dysfunction/ [accessed 2 November 2026]
3. Joint Formulary Committee. (n.d.). Vardenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/vardenafil/ [accessed 2 November 2026]
4. Feldman, H. A., Goldstein, I., Hatzichristou, D. G., Krane, R. J., & McKinlay, J. B. (1994). Impotence and its medical and psychosocial correlates: Results of the Massachusetts Male Aging Study. Journal of Urology, 151(1), 54–61. https://pubmed.ncbi.nlm.nih.gov/8254833/ [accessed 2 November 2026]
5. Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 2 November 2026]

Information on this page is for educational purposes only and is not medical advice. Prescription treatments require clinical assessment by a UK-registered prescriber. Always consult a qualified healthcare professional before starting or changing any medication.