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All medications from licensed pharmacies
GPhC reg. no. 1120610
All medications from licensed pharmacies
GPhC reg. no. 1120610
Mysimba can be used as part of weight loss programme alongside a calorie-controlled diet and physical exercise.
The medicine has been granted a licence for use in Europe and will be available in the UK later in 2017. Mysimba is already available in the USA under a different name (Contrave).
Mysimba is composed of two active substances, namely naltrexone and bupropion. These substances act on the brain. Together they control the amount of food that you eat and energy that you use, and influence your eating behaviour by changing the reward ‘feelings’ (such as cravings and comforts) that you gain from food. Naltrexone works by inhibiting certain opioid receptors on nerve cells and bupropion inhibits the uptake of the natural chemicals known as norepinephrine and dopamine by nerve cells. By changing overall eating habits, this combination medicine helps you to lose weight. Both medicines have previously been used in the treatment of addiction – to tobacco, opioid painkillers, and to alcohol.
From four clinical trials, there is evidence to suggest that over 56 weeks, alongside an intensive behaviour modification programme, people taking the combination naltrexone and bupropion lost a significantly greater amount of body weight (5.0–9.3%) compared with placebo (1.2–5.1%). Compared with placebo, these individuals were also more likely to achieve 5% or more weight loss from baseline to week 56 (45–51% versus 16–19%).
Mysimba is a tablet that is administered twice daily. The dose is increased weekly over 4 weeks. One tablet is taken in the morning in week 1, two tablets (one morning and one evening) in week 2, three tablets (two morning and one evening) in week 3, and the required dose (two morning and two evening) is taken in week 4 and onwards.
Mysimba is taken to compliment a weight loss programme, comprising a calorie-reduced diet and increased physical activity. After 16 weeks, the medicine should be discontinued if a weight loss of 5% or more of initial body weight has not been lost.
Mysimba is used by adults aged of 18 years or more who are obese (body mass index of 30 kg/m2 or greater), or overweight (body mass index of 27 kg/m2 up to 30 kg/m2) with at least one weight-related disorder (such as type 2 diabetes, controlled hypertension, or abnormal blood lipid levels). It is not recommended in children, adolescents, people over aged 75 years, or during pregnancy (or in women trying for a baby) or breast feeding.
Mysimba should not be used if you have experienced hypersensitivity to naltrexone, bupropion, or its other ingredients. Do not take this medicine if you have uncontrolled hypertension, seizures, a central nervous system tumour, history of eating disorders or bipolar disorder, or severe liver or kidney disease. Neither should you start Mysimba if you are undergoing benzodiazepine or alcohol withdrawal, using other naltrexone or bupropion based products, dependent on opiate agonists or chronic opioids, or currently on monoamine oxidase inhibitors or taken them within the last 14 days.
Mysimba is used with caution if you have a history of depression, as it may increase your risk of suicidal behaviour, or have certain clinical characteristics or take other medicines that increase your risk of seizures. Caution is also warranted if you have controlled hypertension, blood vessel diseases, or hereditary disorders related to of galactose intolerance, lactase deficiency, or abnormal absorption of sugars.
The most common adverse event is nausea, which is usually transient and mild to moderate in severity. Very commonly, there are other effects on the gut including vomiting, dry mouth, stomach pain, diarrhoea and constipation. Also common are headache, dizziness; anxiety, agitation, and sleeping difficulties; and muscle and joint pain.
While rare, seek medical attention immediately if you have an allergic reaction, with signs such as face, tongue, and throat swelling; breathing or swallowing problems; itchy rash; and muscle and joint pain.
