Naltrexone and bupropion
Anti-obesity drugs
Anti-obesity drugsPregnancy: avoid
Not used in pregnancy; the prescriber is told at once if pregnancy occurs during treatment.
An extended-release combination of an opioid antagonist and an antidepressant that acts on hunger and reward circuits; used with diet and exercise in obesity.
Quick facts
- Group
- Anti-obesity drugs
- Target
- Hypothalamic appetite and brain reward circuits (opioid receptors and dopamine/noradrenaline reuptake)
- Used for
- Chronic weight management
- Key effects
- Nausea · Constipation or diarrhoea · Headache
- Monitor
- Weight · Blood pressure and heart rate · Mood
- ATC
- A08AA62
No doses: the clinician sets them by the current guideline.
Mechanism of action
Bupropion inhibits the reuptake of dopamine and noradrenaline; naltrexone blocks opioid receptors. Together they are thought to act on the hypothalamic hunger centre and the mesolimbic reward system, reducing appetite and food cravings.
- Bupropion raises dopamine and noradrenaline signalling
- Naltrexone blocks opioid receptors
- Hunger centre and reward system are damped
- Less appetite and fewer food cravings
Indications
- Chronic weight management with a reduced-calorie diet and exercise in obesity, or overweight with weight-related conditions Obesity →
Adverse effects
Common
- Nausea (very common at the start), vomiting
- Constipation or diarrhoea
- Headache, dizziness, insomnia
- Dry mouth, altered taste
- Tremor, sweating, flushing, ringing in the ears
Contraindications
- Seizure disorder, or anorexia nervosa or bulimia
- Uncontrolled high blood pressure
- Chronic opioid use, opioid agonist treatment or acute opioid withdrawal
- Abrupt stopping of alcohol, benzodiazepines, sedatives or antiseizure drugs
- Use of an MAO inhibitor in the past 14 days
- Other bupropion-containing products
Key interactions
- Opioid analgesics and opioid-containing cough or antidiarrhoeal medicines
- Blocked by naltrexone; may precipitate withdrawal; avoided.
- MAO inhibitors (including linezolid and methylene blue)
- Contraindicated; at least 14 days are left between them.
- Other bupropion products
- Duplicate bupropion raises seizure risk.
- Alcohol
- Worsens side effects.
What is monitored
- Weight, to judge whether treatment continues
- Blood pressure and heart rate
- Mood, suicidal thoughts and behaviour, especially early and after dose changes
- Eye pain or vision changes
Administration and safety
- Oral extended-release tablets, swallowed whole, not split, chewed or crushed.
- Started low and increased weekly over the first weeks; taken twice a day.
- Not taken with a high-fat meal.
- Look-alike risk: not given together with other bupropion products (antidepressant or smoking-cessation forms).
Pregnancy and breastfeeding
Not used in pregnancy; the prescriber is told at once if pregnancy occurs during treatment.
Nursing care
- Before: seizure history, eating disorders, blood pressure, opioid use, MAOI use.
- During: blood pressure, pulse, mood and suicidal thinking.
- Teach that opioid pain medicines will not work well and that trying to overcome the block can cause overdose.
- Teach to report seizures, eye pain or rash immediately.
Pharmacokinetics
- Absorption
- Oral extended-release tablet; it is not taken with a high-fat meal.
Test yourself
Think of the answer, then tap the question to see it.
Why can't a patient on naltrexone-bupropion receive usual opioid analgesia?
Naltrexone blocks opioid receptors, so opioids work poorly and may precipitate withdrawal.
Which seizure-related conditions contraindicate naltrexone-bupropion?
Seizure disorder, eating disorders (anorexia, bulimia) or abrupt alcohol or benzodiazepine withdrawal.
Which boxed warning comes from the bupropion component?
Suicidal thoughts and behaviour, especially in young people.
Connections
← Back to the class: Anti-obesity drugs
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Naltrexone and Bupropion: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2019); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.