Vardenafil and Orlistat: Can You Take Them Together?

Vardenafil and Orlistat: Understanding the Interaction

Published: 2 November 2026

Many men wonder whether vardenafil and orlistat can be taken together safely. The good news is that no major interaction is commonly reported between vardenafil (a medicine for erectile dysfunction) and orlistat (a weight-loss medicine). However, both medicines need careful prescriber review, and understanding how each works will help you use them safely and effectively.

What Is Vardenafil?

Vardenafil is a prescription medicine used to treat erectile dysfunction (ED) in adult men [5]. It belongs to a group of medicines called PDE5 inhibitors, which work by relaxing blood vessels in the penis, allowing increased blood flow when you are sexually aroused. Vardenafil is the generic version of the branded medicine Levitra.

Vardenafil is typically taken about 25 to 60 minutes before sexual activity, and its effects can last for several hours [5]. It is available in 5mg, 10mg, and 20mg tablets. 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, indigestion, and nasal congestion [5]. Vardenafil is not suitable for everyone, particularly men taking nitrates for chest pain, those with severe heart or liver problems, or men who have had recent strokes or heart attacks. Your prescriber will check your full medical history and current medicines before prescribing vardenafil.

What Is Orlistat?

Orlistat is a medicine used to help with weight loss in adults who are overweight or obese. It is available on prescription (Xenical 120mg) or over the counter from pharmacies (Alli 60mg) after a consultation. Orlistat works in your digestive system by blocking about one-third of the fat from the food you eat from being absorbed.

The unabsorbed fat is then passed out of your body in your stools. Orlistat is most effective when combined with a reduced-calorie, lower-fat diet and regular physical activity. It is typically taken three times a day with meals that contain fat, or up to one hour after eating. If you miss a meal or eat a meal with no fat, you can skip that dose.

Common side effects of orlistat are related to its mechanism of action and include oily or fatty stools, increased bowel movements, flatulence with discharge, and urgent bowel movements. These effects are more likely if you eat meals high in fat. Orlistat can also reduce the absorption of fat-soluble vitamins (A, D, E, and K), so a multivitamin supplement taken at bedtime is often recommended.

Can You Take Vardenafil and Orlistat Together?

There is no major documented interaction between vardenafil and orlistat, and they can generally be taken together safely. Orlistat works in the gut to block fat absorption and does not significantly affect the way vardenafil is processed in the body. Vardenafil is broken down mainly by liver enzymes (CYP3A4), and orlistat does not interfere with these enzymes in a clinically meaningful way.

However, it is important to remember that every person's situation is different. Your prescriber or pharmacist will review all your current medicines, health conditions, and lifestyle factors during your consultation to ensure both medicines are suitable for you. You should always declare every medicine you take—prescription, over-the-counter, herbal, or supplements—so that your healthcare professional can check for any potential issues.

While the combination of vardenafil and orlistat is not known to cause problems, both medicines have their own side effects and precautions. For example, vardenafil can lower blood pressure slightly, and if you are also taking blood pressure medicines, this needs careful monitoring. Orlistat can cause gastrointestinal side effects that may be uncomfortable, and these should be managed with dietary changes.

How the Medicines Work Differently

Vardenafil acts on blood vessels in the penis to improve blood flow during sexual arousal, while orlistat acts in the digestive system to prevent fat absorption. Because they work in completely different parts of the body and through different mechanisms, they do not interfere with each other's effectiveness. This makes the combination generally safe from a pharmacological standpoint, provided both medicines are appropriate for you individually.

What Your Prescriber Checks Before Prescribing Vardenafil

Before prescribing vardenafil, your prescriber will ask about your medical history, current medicines, and overall health [2]. They will specifically check whether you have heart problems, high or low blood pressure, liver or kidney disease, blood disorders, stomach ulcers, or a history of stroke. They will also ask about any eye problems, particularly a condition called non-arteritic anterior ischaemic optic neuropathy (NAION), which causes sudden vision loss.

Your prescriber must know about every medicine you take. Vardenafil must never be taken with nitrates (such as GTN spray, isosorbide mononitrate, or isosorbide dinitrate), nicorandil, riociguat, or recreational drugs called 'poppers' (amyl or alkyl nitrites), as this combination can cause a dangerous drop in blood pressure [5]. If you take alpha-blockers for prostate problems or blood pressure (such as tamsulosin or doxazosin), you will need to start on a low dose of vardenafil and be monitored carefully.

Certain medicines that affect liver enzymes can alter vardenafil levels in your blood. Potent CYP3A4 inhibitors (such as ritonavir, ketoconazole, itraconazole, clarithromycin, or Paxlovid) can increase vardenafil levels, and vardenafil is contraindicated or requires dose adjustment with these medicines [5]. Your prescriber will review the summary of product characteristics (SmPC) for any medicine you take to ensure vardenafil is safe for you.

Declaring Orlistat and Other Medicines

When you complete your online consultation for vardenafil, make sure you list orlistat and any other medicines, vitamins, or supplements you take. Even though orlistat does not interact with vardenafil, your prescriber needs a complete picture of your health. For example, if you are taking orlistat because you are overweight, your prescriber may also want to check your blood pressure, cholesterol, and blood sugar, as these can affect both heart health and erectile function [1][2].

Practical Advice for Taking Vardenafil and Orlistat

If you are taking both vardenafil and orlistat, here are some practical tips to help you get the best results from each medicine. Take vardenafil about 25 to 60 minutes before you plan to have sex, on an empty stomach or after a light meal [5]. High-fat meals can delay how quickly vardenafil works, so if you are taking orlistat with a meal, consider timing your vardenafil dose separately—for example, take vardenafil later in the evening if you had orlistat with dinner.

Orlistat should be taken with each main meal that contains fat, or up to one hour after eating. To minimise side effects such as oily stools and urgency, follow a lower-fat diet (no more than about 30% of calories from fat) and spread your fat intake evenly across three meals. Avoid high-fat meals, especially on days when you plan to take vardenafil, as a heavy, fatty meal can reduce vardenafil's effectiveness and worsen orlistat's gastrointestinal side effects.

Stay well hydrated, especially if you experience loose stools from orlistat. Limit alcohol, as heavy drinking can worsen erectile dysfunction and add to the blood-pressure-lowering effect of vardenafil, increasing the risk of dizziness [1][5]. If you take a multivitamin supplement (recommended with orlistat), take it at bedtime, at least two hours after your last dose of orlistat, to ensure proper absorption of fat-soluble vitamins.

Warning Signs and When to Seek Help

While vardenafil and orlistat are generally well tolerated, you should be aware of warning signs that require urgent medical attention. If you experience an erection lasting more than four hours (priapism), seek emergency help immediately, as this can cause permanent damage to the penis [5]. Sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing (sometimes with ringing in the ears or dizziness), requires urgent medical assessment.

If you develop chest pain during or after sexual activity, do not take more vardenafil and seek medical advice promptly [5]. Do not take nitrates (GTN spray) to relieve chest pain if you have taken vardenafil in the past 24 hours, as this combination is dangerous. Contact your GP or call 999 if you have severe chest pain.

With orlistat, seek medical advice if you develop severe abdominal pain, as rare cases of liver problems have been reported. If you notice dark urine, pale stools, yellowing of the skin or eyes, or persistent nausea, stop orlistat and contact your GP. If you experience severe or persistent diarrhoea while taking orlistat, this can reduce the effectiveness of other medicines (including oral contraceptives), so speak to your pharmacist or GP.

Reporting Side Effects

If you experience side effects from vardenafil or orlistat, talk to your prescriber or pharmacist. You can also report side effects directly via the Yellow Card Scheme at www.mhra.gov.uk/yellowcard or search for 'Yellow Card' in the Google Play or Apple App Store. Reporting side effects helps improve the safety information available about medicines.

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]

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.