Mysimba
A prolonged-release tablet combining naltrexone and bupropion, authorised in the EU for weight management in adults alongside diet and physical activity.
General information, not medical advice. Docalo does not sell medicines, and prescription-only medicines are prescribed only after an individual medical assessment.
What Mysimba is and how it works
Mysimba combines two older medicines: naltrexone, which blocks opioid receptors, and bupropion, which acts on dopamine and noradrenaline. Together they act on the brain areas that control appetite and food reward.
In 2025 the European Medicines Agency completed a safety review that kept the authorisation in place, with an annual check of continued benefit and cardiovascular risk and an ongoing heart-safety study.
Who it may suit, according to the label
- Adults with a BMI of 30 kg/m² or more, or 27 kg/m² or more with a weight-related condition such as type 2 diabetes, high blood fats or controlled high blood pressure.
- Used alongside a reduced-calorie diet and increased physical activity.
- Stopped after 16 weeks if at least 5% of the starting body weight has not been lost.
Only a doctor who knows your history can decide whether a medicine suits you.
How to use Mysimba
Built up over four weeks. The product information starts with one tablet in the morning in week one and adds one tablet each week, reaching two tablets twice a day from week four.
Swallowed whole. Swallow the tablets whole with water; do not cut, chew or crush them.
Reviewed every year. The prescriber reviews treatment after 16 weeks and then every year, and stops it if the benefit is not maintained.
Common side effects
Get urgent medical help if (whatever the frequency): A seizure or fit, Thoughts of harming yourself, or a sudden change in mood or behaviour, Swelling of the face, lips, tongue or throat, or trouble breathing
Very common (may affect more than 1 in 10 people): nausea, vomiting, constipation, headache
Common (may affect up to 1 in 10 people): dizziness, trouble sleeping, dry mouth, tremor, anxiety, tiredness
Safety
Do not use Mysimba if
- You have uncontrolled high blood pressure
- You have, or have had, a seizure disorder, a brain tumour, or an eating disorder such as bulimia or anorexia
- You take opioids, are in opioid withdrawal, or are stopping alcohol or benzodiazepines abruptly
- You have bipolar disorder, have taken an MAO inhibitor in the last 14 days, or have severe liver or end-stage kidney disease
Blood pressure and pulse are checked before and during treatment. Always read the patient leaflet supplied with the tablets.
Your questions answered
Is Mysimba the same as Contrave?
When is Mysimba stopped?
More questions
Can Mysimba be taken with opioid painkillers?
References
This page summarises the official product information and the published sources below.
- Mysimba (naltrexone / bupropion): European public assessment report European Medicines Agency, 2015
- Mysimba 8 mg/90 mg prolonged-release tablets: Summary of Product Characteristics electronic medicines compendium (emc), 2026
- EMA concludes review of weight management medicine Mysimba European Medicines Agency, 2025
- Mysimba: Article 20 referral European Medicines Agency, 2025
- Effect of naltrexone plus bupropion on weight loss in overweight and obese adults (COR-I). Lancet 2010;376:595-605 The Lancet, 2010
Other medicines used in weight management
Talk to a doctor about weight care
The Docalo membership gives you a doctor's assessment, a personalised plan and monthly follow-up. Your doctor decides what care suits you, with or without medicine.
Talk to a doctor about weight careGeneral information, not medical advice. Docalo does not sell medicines, and prescription-only medicines are prescribed only after an individual medical assessment.
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