Mysimba (bupropion/naltrexone) 8 mg + 90 mg, 112 tablets: profile, composition and research

Reference page for Mysimba (bupropion/naltrexone) 8 mg + 90 mg, 112 tablets. Active substance: Бупропион + налтрексон / Bupropion + naltrexone.

Key facts

What the bupropion and naltrexone combination is

Mysimba is a prescription medicine for weight reduction that contains two active substances, bupropion and naltrexone. Each tablet holds 8 mg of naltrexone hydrochloride and 90 mg of bupropion hydrochloride, equivalent to 7.2 mg of naltrexone and 78 mg of bupropion.

Bupropion affects dopamine and noradrenaline signalling in the central nervous system. Naltrexone is an opioid receptor antagonist, and in this combination it works differently from its role in treating dependence, where it is given in other amounts and by other schedules.

The medicine is used in adults with overweight and obesity as an addition to diet and physical activity, not as a substitute for them. A pack contains 112 tablets, intended for the stepwise selection of the dose over several weeks. Dose selection and any change are made only on a physician's instruction.

How the combination acts

Central action

Both substances act on brain regions that govern how much food is eaten and how much energy is spent. Together they alter the signals linked to appetite and to the feeling of fullness, and so to the sense of hunger between meals. This is what links the two substances.

The part naltrexone plays

Bupropion increases activity in the reward system, while naltrexone blocks opioid receptors that can blunt that effect. With that addition the action of bupropion is kept going for longer than with bupropion alone. That explains why the two are used together.

The practical result

In some patients appetite and food cravings are reduced, which makes a chosen eating pattern easier to keep to. Response is individual, so the medicine is treated as one element of a weight-management programme. Without lifestyle change the effect is limited.

Approved uses

The prescribing information covers adults with obesity and a body mass index of 30 kg/m² or above, or with overweight and a body mass index from 27 kg/m² together with weight-related risk factors such as metabolic disorders. The precise criteria are assessed by a physician.

The medicine is given in addition to a programme that lowers calorie intake and raises physical activity. Treatment involves a stepwise build-up to the working dose, which a physician plans week by week with tolerability in mind. The dose should not be changed on one's own.

Use in patients over 65 calls for caution, and it is not recommended over the age of 75. The dose and the duration are set by a physician, not by a reference page, after the expected benefits and risks have been weighed. Such a decision follows an examination and tests.

What the research shows

The combination was studied in the COR programme. In COR-I, in adults with overweight and obesity, the combination alongside lifestyle change was accompanied by greater weight loss than placebo, and by improvement in some related measures. Both trials looked at weight and related measures.

COR-II confirmed these results in a larger group and also assessed weight-related risk factors. Separate work looked at the combination in binge-eating disorder, where a positive effect was also reported. The evidence base for these uses continues to grow.

Reviews and meta-analyses place naltrexone with bupropion among medicines of moderate efficacy for weight reduction. The adverse-event profile is described in detail in the literature, so the decision to prescribe stays with a physician. The medicine is one option rather than the only one.

Published research

Primary sources, verified against PubMed:

• Effect of naltrexone plus bupropion on weight loss in overweight and obese adults (COR-I): a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial., PubMed 20673995 (Lancet (London, England), 2010).
• A randomized, phase 3 trial of naltrexone SR/bupropion SR on weight and obesity-related risk factors (COR-II)., PubMed 23408728 (Obesity (Silver Spring, Md.), 2013).
• Naltrexone-Bupropion and Behavior Therapy, Alone and Combined, for Binge-Eating Disorder: Randomized Double-Blind Placebo-Controlled Trial., PubMed 36285406 (The American journal of psychiatry, 2022).
• The efficacy and safety of the naltrexone/bupropion combination for the treatment of obesity: an update., PubMed 26188223 (Hormones (Athens, Greece), 2015).

Listed for reference. Publication of a study is not a claim about this particular product.

Precautions

• This is a prescription medicine. Prescribing and dose selection belong to a physician.
• It is not used in uncontrolled hypertension, epilepsy or a history of seizures, bipolar disorder, CNS tumours, or severe liver and kidney impairment.
• Nausea, vomiting, constipation, headache, sleep disturbance, anxiety and a rise in blood pressure are possible.
• Seizures have been reported during treatment; if they occur, the medicine is stopped and a doctor is contacted.
• It is not used in pregnancy or breastfeeding; reliable contraception is needed during treatment.
• Combining it with alcohol raises the risk of seizures and psychiatric reactions. Tell your doctor about every medicine you take.

Frequently asked