Mysimba

Mysimba is an oral weight loss treatment that was approved for treatment in the EU in 2015. It is manufactured by Orexigen and is available as prolonged-release tablets.

Mysimba contains two active ingredients: naltrexone and bupropion.

These two ingredients, when taken together, help to regulate your appetite by boosting your metabolism. This will help you feel fuller and consume fewer calories, which will help you lose weight over time.

Mysimba also affects how the brain perceives food. It helps to reduce the pleasure signals sent to your brain from eating food. This helps to reduce cravings, which help you eat less.

A 2010 clinical trial including 1453 patients found that Mysimba was more effective than a placebo for weight loss.

They found 48% of patients on Mysimba lost at least 5% of their original body weight after 56 weeks of treatment, compared to 16% of those on the placebo.

25% of patients on Mysimba lost at least 10% of their original body weight, compared to just 7% of patients on the placebo.

You need to take Mysimba for at least 16 weeks to see the effects of the medicine. However, based on clinical trials, it may take up to 24 weeks (6 months) to see significant results. If you have not seen any weight loss after 16 weeks, your doctor may consider an alternative.

You can use Mysimba if you have a certain body mass index (BMI). This includes those who have:

• a BMI of 30 or above
• a BMI of 27 or above and have one weight-related health condition

Eligible weight-related health conditions include:

• prediabetes
• type 2 diabetes
• high blood pressure
• heart disease (including high cholesterol, heart attack, stroke, coronary artery disease) 
• obstructive sleep apnoea
• PCOS (polycystic ovarian syndrome)
• osteoarthritis or gout
• chronic back pain
• fatty liver disease
• gallbladder disease

You may not be able to use Mysimba if you have a certain medical condition or take certain medicines. It’s important you list all medical conditions you have and any medicine you take during the consultation. This is so our doctors can ensure it’s safe for you to take.

Each Mysimba contains 8 mg of naltrexone and 90 mg of bupropion.

You start by taking 1 tablet once daily for 1 week, and then increase the dose each week.

Mysimba is safe to take for long-term use. So, you can take Mysimba up until you reach a healthy weight or BMI.

Like all prescription medicines, Mysimba may cause side effects. The most common side effects should go away on their own once your body gets used to the medicine.

Very common side effects (fewer than 1 in 10 people):

• Feeling sick (nausea) - you can reduce nausea by eating little and often and prioritising bland foods like plain toast, rice or crackers.
• Constipation - you can manage constipation yourself by upping the fiber in your diet such as with fruits or wholegrains and by drinking more water.

Common side effects (up to 1 in 10 people):

• Dizziness - try to stay hydrated and avoid getting up too quickly or making sudden movements.
• Headaches - drink plenty of water, avoid caffeine and try to keep a healthy sleep schedule.
• Dry mouth - try chewing gum to stimulate saliva production and avoid caffeine, alcohol or tobacco.
• Sleep problems - avoid taking Mysimba too close to your bed time and make sure your bedroom is dark, cool and quiet.

Speak to your doctor as soon as possible if you experience any persistent or serious side effects. If you experience any rare side effects such as fits or suicidal thoughts, seek emergency medical attention.

For a full list of side effects, please refer to the patient information leaflet (PIL) which comes in the box with your medicine.

You should drink as little as possible or not at all while on Mysimba. Drinking excessive amounts of alcohol may increase the risk of experiencing fits (seizures). If you do drink a lot and are considering taking Mysimba, you should not stop drinking suddenly, as this can also increase the risk of seizures.

Yes, Mysimba is a safe and clinically-proven weight loss treatment. But if you have another medical condition or take other medication, your doctor will need to ensure it’s safe for you. Our doctors will also know whether it’s safe for you based on your medical questionnaire during the ordering process.

No, Mysimba is not available without a prescription. You need a valid prescription from a healthcare professional to purchase it. This ensures the medication is safe and suitable for your needs.