Mysimba 8 mg/90 mg Prolonged-Release Tablets

Active ingredients: Naltrexone hydrochloride / Bupropion hydrochloride
Form: Prolonged-release tablets
Administration: Oral use
Treatment type: Prescription weight-management medicine
Suitable for: Eligible adults with obesity or overweight with weight-related health conditions

What Is Mysimba?

Mysimba is a prescription-only oral medicine used to support weight management in eligible adults. Each prolonged-release tablet contains 8 mg naltrexone hydrochloride and 90 mg bupropion hydrochloride, equivalent to 7.2 mg naltrexone and 78 mg bupropion.

Mysimba is intended to be used alongside a reduced-calorie diet and increased physical activity rather than as a replacement for healthy lifestyle changes.

It may be prescribed for adults aged 18 years and over with:

• a BMI of 30 kg/m² or above (obesity); or
• a BMI of 27 kg/m² to below 30 kg/m² (overweight) when accompanied by one or more weight-related conditions, such as type 2 diabetes, abnormal blood lipid levels or controlled high blood pressure.

Treatment suitability must be assessed by a qualified prescriber.

How Does Mysimba Work?

Mysimba combines two active ingredients, naltrexone and bupropion, which act on areas of the brain involved in appetite, food intake and the reward associated with eating.

Bupropion influences the activity of the neurotransmitters dopamine and noradrenaline, while naltrexone acts on opioid receptors.

Although the complete mechanism behind Mysimba’s weight-management effects is not fully understood, the combination is thought to influence brain pathways responsible for hunger, food cravings, eating behaviour and energy balance.

For some patients, this can make it easier to reduce calorie intake and maintain dietary changes as part of a structured weight-management programme.

What Are the Benefits of Mysimba?

Mysimba provides a non-injectable option for eligible adults who require additional support with weight management.

Potential benefits include:

• Oral treatment – Mysimba is supplied as tablets rather than injections.
• Appetite management – it acts on brain pathways involved in hunger and food intake.
• Reduced food cravings – its effects on reward pathways may help some patients manage urges to eat.
• Gradual dose escalation – treatment is introduced progressively over four weeks to reach the recommended maintenance dose.
• Used alongside lifestyle changes – Mysimba is designed to complement a calorie-controlled diet and increased physical activity.
• Clinically evaluated treatment – naltrexone/bupropion has been studied in clinical weight-management trials.

Individual weight-loss results vary considerably and treatment should be regularly reviewed by a healthcare professional.

How Effective Is Mysimba?

Clinical studies involving adults with overweight or obesity have shown that naltrexone/bupropion can produce greater average weight reduction than placebo when both groups also receive dietary and physical-activity support.

Mysimba is not expected to work sufficiently for everyone. For this reason, treatment response must be assessed.

Treatment should be discontinued after 16 weeks if you have not lost at least 5% of your initial body weight.

Continued treatment should also be reassessed regularly by your healthcare professional.

How Do I Take Mysimba?

Mysimba tablets are taken orally and should be swallowed whole with water. They should preferably be taken with food.

The tablets must not be cut, crushed or chewed, because they are formulated to release the active ingredients gradually.

Treatment normally begins with a low dose that is progressively increased over four weeks.

Mysimba Dosage Schedule

The standard dose-escalation schedule is:

Treatment period	Morning	Evening	Total tablets per day
Week 1	1 tablet	—	1
Week 2	1 tablet	1 tablet	2
Week 3	2 tablets	1 tablet	3
Week 4 onward	2 tablets	2 tablets	4

The standard maximum recommended daily dose is two tablets twice daily, providing a total of 32 mg naltrexone hydrochloride and 360 mg bupropion hydrochloride per day.

Some patients, including those with certain kidney or liver problems, may require a different maximum dose or may not be suitable for treatment. Always follow the dosage prescribed specifically for you.

What If I Miss a Dose?

If you miss a dose of Mysimba, do not take an additional dose to compensate.

Take your next prescribed dose at the normal scheduled time.

Do not double your dose.

Who Can Take Mysimba?

Mysimba may be considered for adults aged 18 years or older who meet the relevant BMI criteria and for whom treatment is considered clinically appropriate.

Before prescribing Mysimba, a healthcare professional should review factors including:

• your BMI and weight-management history;
• blood pressure;
• current and previous medical conditions;
• current medicines;
• seizure history;
• mental-health history;
• kidney and liver function where relevant;
• use of opioid medicines;
• pregnancy or plans to become pregnant.

Mysimba is not intended for children or adolescents under 18 years.

It should be used with caution in people over 65 and is not recommended for people over 75 according to current product information.

Who Should Not Take Mysimba?

Mysimba is not suitable for everyone.

You should not take Mysimba if you have certain conditions or circumstances, including:

• an allergy to naltrexone, bupropion or another ingredient in the medicine;
• uncontrolled high blood pressure;
• a current seizure disorder or previous history of seizures;
• a known tumour of the central nervous system;
• a history of bipolar disorder;
• a current or previous diagnosis of bulimia or anorexia nervosa;
• severe liver impairment;
• end-stage kidney failure;
• current dependence on chronic opioids or opioid agonists such as methadone;
• acute opioid withdrawal;
• acute withdrawal from alcohol or benzodiazepines;
• treatment with another medicine containing naltrexone or bupropion;
• treatment with certain monoamine oxidase inhibitors (MAOIs).

Other contraindications and precautions may apply. Your prescriber should assess your complete medical history before treatment begins.

Mysimba and Opioid Medicines

This is a particularly important consideration with Mysimba.

Naltrexone blocks opioid receptors, which means opioid-containing medicines may not work normally while Mysimba is being taken.

This can affect opioid painkillers and potentially other medicines containing opioids.

Tell your doctor, pharmacist, dentist or other healthcare professional that you take Mysimba before receiving treatment that might involve an opioid medicine.

Do not attempt to overcome naltrexone’s opioid-blocking effect by taking larger amounts of an opioid. This can be dangerous.

If you currently require chronic opioid treatment, Mysimba may not be appropriate for you.

Mysimba and Blood Pressure

Mysimba can cause increases in blood pressure and heart rate in some patients.

Blood pressure and pulse should therefore be assessed before treatment and monitored where clinically appropriate.

Mysimba must not be used in patients with uncontrolled hypertension.

Speak with your healthcare professional if you develop symptoms that concern you or if you have an existing cardiovascular condition.

Mysimba and Seizures

Bupropion is associated with a dose-related risk of seizures.

Mysimba is therefore contraindicated in people who currently have a seizure disorder or who have previously experienced seizures.

Certain medicines and medical circumstances can also increase seizure risk. Your prescriber should review your medical history and medications before deciding whether Mysimba is appropriate.

Never take more Mysimba than prescribed.

Common Side Effects of Mysimba

Like all medicines, Mysimba can cause side effects, although not everyone experiences them.

Very common side effects include:

• nausea;
• vomiting;
• constipation.

Other commonly reported effects can include:

• dizziness;
• dry mouth;
• headache;
• sleeping difficulties;
• changes in appetite;
• gastrointestinal discomfort.

Some adverse reactions can be serious and require medical attention.

Read the Patient Information Leaflet supplied with your medicine for the complete list of side effects and their frequencies.

When Should I Seek Medical Advice?

Contact a healthcare professional if you develop persistent or troublesome side effects.

Seek urgent medical attention if you experience potentially serious symptoms such as:

• a seizure;
• a severe allergic reaction;
• significant changes in mood, behaviour or mental wellbeing;
• severe or uncontrolled increases in blood pressure;
• other severe or rapidly worsening symptoms.

If you experience dizziness, drowsiness, loss of consciousness or a seizure, do not drive or operate machinery until the symptoms have completely resolved and you have received appropriate medical advice.

Mysimba and Mental Health

Because Mysimba contains bupropion, your prescriber should consider your mental-health history before prescribing treatment.

Tell your healthcare professional if you have previously experienced significant psychiatric conditions, including bipolar disorder.

Seek medical advice if you experience significant changes in mood, behaviour or thoughts while taking the medicine.

Can I Take Mysimba During Pregnancy?

Mysimba should not be used for weight reduction during pregnancy.

If you are pregnant, think you may be pregnant, are planning a pregnancy or become pregnant while taking Mysimba, contact your healthcare professional for advice.

Your prescriber can advise you about stopping treatment and appropriate weight-management care during pregnancy.

Can I Drink Alcohol While Taking Mysimba?

Alcohol can be relevant to the safety of bupropion-containing medicines.

Heavy alcohol use and suddenly stopping heavy alcohol consumption can affect seizure risk. Mysimba is contraindicated during acute alcohol withdrawal.

Discuss your alcohol consumption with your prescriber before treatment and follow their advice about alcohol while taking Mysimba.

Can Mysimba Be Taken With Other Medicines?

Mysimba can interact with a number of medicines.

Tell your prescriber about all medicines you currently take, including prescription medicines, over-the-counter products and supplements.

Particular consideration is required with medicines such as:

• opioid painkillers and other opioid-containing products;
• MAO inhibitors;
• other medicines containing bupropion or naltrexone;
• certain antidepressants and antipsychotics;
• medicines that can lower the seizure threshold;
• some medicines for diabetes;
• levodopa or amantadine;
• certain sedating medicines and other treatments that may interact with its active ingredients.

Never start, stop or change another medicine because of Mysimba without appropriate medical advice.

Mysimba and Diabetes

Mysimba may be considered for certain adults who are overweight and have type 2 diabetes, provided treatment is clinically appropriate.

Weight reduction can affect blood glucose levels. People taking insulin or some other diabetes medicines may therefore require closer monitoring because changes in glucose control can increase the risk of hypoglycaemia.

Your diabetes medication should only be adjusted by an appropriate healthcare professional.

Mysimba vs GLP-1 Weight Loss Injections

Mysimba works differently from GLP-1-based treatments such as Wegovy and from dual GIP/GLP-1 medicines such as Mounjaro.

Mysimba contains naltrexone and bupropion and primarily influences brain pathways involved in appetite, food intake and reward.

Wegovy contains semaglutide, a GLP-1 receptor agonist.

Mounjaro contains tirzepatide, which acts on both GIP and GLP-1 receptors.

Mysimba is an oral tablet, whereas commonly used Wegovy and Mounjaro presentations are injections.

The most appropriate treatment cannot be determined solely by which medicine produces greater average weight loss. Medical history, contraindications, other medicines, side effects, previous treatment and individual preferences should all be considered by a prescriber.

How Long Can I Take Mysimba?

Your response should first be assessed after 16 weeks.

If you have not lost at least 5% of your starting body weight, Mysimba should be discontinued because you are unlikely to receive sufficient benefit from continuing treatment.

If treatment is effective and tolerated, continued use still requires medical review.

Current European recommendations also require the need for continued treatment to be re-evaluated annually.

Mysimba and Long-Term Cardiovascular Safety

European regulators have recently reviewed the cardiovascular safety of Mysimba.

The European Medicines Agency concluded that the medicine’s benefits continue to outweigh its risks when used appropriately. Available evidence has not identified a cardiovascular safety concern for treatment lasting up to 12 months, but there remains uncertainty regarding cardiovascular safety beyond one year.

For this reason, long-term treatment requires ongoing clinical review, and additional research into cardiovascular outcomes is continuing.

Patients with cardiovascular risk factors should make sure their prescriber is aware of their complete medical history.

How Should Mysimba Be Stored?

Keep Mysimba in its original packaging and follow the storage instructions printed on the package and Patient Information Leaflet.

Keep all medicines:

• out of the sight and reach of children;
• protected from unsuitable environmental conditions;
• in their original packaging where instructed.

Do not use Mysimba after the expiry date shown on the packaging.

Can I Buy Mysimba Online?

Mysimba is a prescription-only medicine.

Where legally available through MySlimCare, treatment should only be supplied after an appropriate medical consultation and assessment by a qualified prescriber.

During your consultation, you may be asked about your:

• height and weight;
• BMI;
• medical history;
• blood pressure;
• current medications;
• previous weight-management treatments;
• kidney and liver health;
• mental-health history;
• opioid use;
• other factors relevant to treatment safety.

If Mysimba is considered appropriate, the prescriber can issue treatment according to the applicable prescribing and dispensing requirements.

Mysimba FAQs

Does Mysimba suppress appetite?

Mysimba acts on areas of the brain involved in appetite, food intake and the reward associated with eating. This can help some patients reduce hunger, manage food cravings and consume fewer calories.

How quickly does Mysimba work?

Individual responses vary. Mysimba is gradually increased over the first four weeks, and weight-management progress should be monitored throughout treatment. A key assessment takes place after 16 weeks. Treatment should be discontinued if at least 5% of the patient’s initial body weight has not been lost by that point.

Is Mysimba a GLP-1 medicine?

No. Mysimba is not a GLP-1 receptor agonist. It contains naltrexone and bupropion and works through different neurological pathways from medicines containing semaglutide or tirzepatide.

Is Mysimba an injection?

No. Mysimba is an oral prolonged-release tablet.

How many Mysimba tablets do I take?

Treatment usually begins with one tablet each morning during week 1 and is gradually increased. The standard maintenance dose from week 4 is two tablets in the morning and two in the evening. Some patients require a lower maximum dose because of their medical circumstances. Always take the dose prescribed specifically for you.

Should Mysimba be taken with food?

The tablets should preferably be taken with food and swallowed whole with water. They should not be crushed, cut or chewed.

What happens if Mysimba does not work?

If you have not lost at least 5% of your initial body weight after 16 weeks, treatment should be stopped and alternative weight-management options discussed with your healthcare professional.

Can I take Mysimba with Wegovy or Mounjaro?

Weight-management medicines should not be combined unless a qualified prescriber has specifically determined that the combination is appropriate. Do not independently combine Mysimba with Wegovy, Mounjaro or another prescription weight-management medicine.

Is Mysimba suitable for everyone?

No. Mysimba has several important contraindications, including uncontrolled hypertension, seizure disorders, certain eating disorders, bipolar disorder, severe liver impairment, end-stage kidney failure and certain forms of opioid use. A medical assessment is required before treatment.

Is Mysimba prescription-only?

Yes. Mysimba is a prescription medicine and requires an assessment by an appropriately qualified healthcare professional before it can be prescribed.

---

Important medical information: Mysimba is a prescription-only medicine. Treatment should only be started following assessment by an appropriately qualified healthcare professional. This page is intended to provide general information and does not replace the Patient Information Leaflet, official product information or individual medical advice.