TL;DR

• Mysimba combines naltrexone+bupropion to curb appetite and cravings.
• Average 5‑10% body‑weight loss after 12months, comparable to Qsymia but less than GLP‑1 drugs.
• Common side‑effects: nausea, headache, insomnia; serious risks include increased blood pressure.
• Alternatives include Contrave (same combo in US), Qsymia, Orlistat, Saxenda, Wegovy.
• Choosing depends on BMI, comorbidities, cost and tolerance.

Mysimba is a prescription weight loss medication that merges Naltrexone and Bupropion. Approved by the European Medicines Agency in 2015, it targets the central reward pathways to lower food intake while also moderating cravings.

How Mysimba Works: Mechanism and Clinical Profile

The combination exploits two distinct neuro‑chemical actions:

1. Naltrexone is an opioid‑receptor antagonist that blocks the feedback loop that amplifies the pleasure of eating.
2. Bupropion is a norepinephrine‑dopamine reuptake inhibitor that stimulates the pro‑opiomelanocortin (POMC) neurons, enhancing satiety.

When taken together, the drugs synergise, producing a net reduction in appetite and an increase in energy expenditure. Clinical trials (e.g., the COR‑I study) reported a mean weight loss of 5.5% after one year, with up to 20% of participants achieving ≥10% loss.

Key Attributes of Mysimba

• Dosage: Two tablets daily (each tablet contains 8mg naltrexone+90mg bupropion). Titration over two weeks mitigates nausea.
• Eligibility: Adults with BMI ≥30kg/m² or ≥27kg/m² with at least one weight‑related comorbidity (e.g., hypertension, type2 diabetes).
• Common Side‑effects: Nausea, headache, dry mouth, insomnia, constipation.
• Serious Risks: Elevated blood pressure, potential seizure risk (especially if patient has a history of seizures), hepatic impairment.
• Cost (Australia, 2025): ApproxAU$150‑180 per month, depending on pharmacy and bulk‑order discounts.

Major Alternatives on the Market

Below are the most frequently prescribed obesity drugs that sit alongside Mysimba. Each is introduced with its core attributes so you can see where they overlap or diverge.

Contrave (U.S. brand name) mirrors Mysimba’s exact formula-naltrexone+bupropion-but follows a slightly different titration schedule and has FDA‑specific labeling.

Qsymia couples phentermine (a sympathomimetic) with topiramate (an anticonvulsant). It delivers higher average weight loss (≈9‑10% at 12months) but carries a stronger cardiovascular warning.

Orlistat inhibits pancreatic lipase, preventing absorption of about 30% of dietary fat. Its mechanism is purely peripheral, leading to modest weight loss (≈3‑5%) and notable gastrointestinal side‑effects.

Saxenda (liraglutide) is a GLP‑1 receptor agonist administered daily via injection. It offers 5‑8% weight loss and improves glycaemic control, but requires daily shots and higher cost.

Wegovy (semaglutide) is a once‑weekly GLP‑1 analogue that delivers the strongest results-≈15% body‑weight reduction in a year-but comes with the highest price tag and gastrointestinal side‑effects.

Side‑by‑Side Comparison

Choosing the Right Option for You

Decision‑making boils down to three practical axes:

1. Clinical profile: If you have hypertension or a seizure history, Mysimba may be off‑limits, steering you toward Orlistat or a GLP‑1 drug.
2. Weight‑loss goal: For moderate loss (5‑10%) with oral therapy, Mysimba, Contrave or Qsymia fit. For aggressive targets (>12%) and you’re comfortable with injections, Wegovy or Saxenda are better bets.
3. Budget & coverage: Public health schemes in Australia often subsidise Orlistat and occasionally GLP‑1 drugs under special criteria. Mysimba sits in a mid‑range price band, making it a realistic everyday choice for many patients.

Always discuss with a prescriber who can run baseline labs (liver function, blood pressure, psychiatric screen) before committing.

Practical Tips for Maximising Results

• Start with a low dose for two weeks; this eases gastrointestinal discomfort.
• Pair medication with a structured diet-Mediterranean‑style or a calorie‑controlled plan yields the best synergy.
• Track weight weekly, not daily; fluctuations can mask true trends.
• Monitor blood pressure every month when on Mysimba or Qsymia.
• If side‑effects persist after four weeks, ask your doctor about switching to a GLP‑1 analogue.

Related Concepts and Next Steps

Weight‑loss pharmacotherapy doesn’t exist in a vacuum. Understanding the surrounding landscape helps you stay informed:

• Body Mass Index (BMI): The standard metric for eligibility; a BMI≥30 qualifies for most drugs.
• Metabolic syndrome: Often co‑occurs with obesity; drugs like Mysimba can improve insulin sensitivity.
• Lifestyle interventions: Exercise, sleep hygiene, and mindful eating amplify medication benefits.
• Regulatory status: The Therapeutic Goods Administration (TGA) in Australia has specific prescribing rules for each drug.
• Future directions: Emerging oral semaglutide and dual‑agonist combos may shift the market soon.

After you’ve picked a drug, the next logical read is a guide on “Designing a Sustainable Weight‑Loss Meal Plan” or “Understanding GLP‑1 Therapy Side‑Effects.” Those topics sit just beneath this article in the broader obesity‑treatment knowledge tree.

Frequently Asked Questions

How long does it take for Mysimba to show results?

Most patients notice a modest appetite reduction within the first two weeks of full‑dose therapy. Clinically significant weight loss (≥5% of body weight) usually emerges after 12‑16 weeks, provided diet and activity are controlled.

Can I take Mysimba with other antidepressants?

Bupropion can interact with other serotonergic agents, raising seizure risk. Always disclose all psychiatric meds to your prescriber; many clinicians adjust the dose or opt for a non‑bupropion option like Orlistat.

Is Mysimba safe for people with type2 diabetes?

Yes, it is often prescribed for diabetic patients because the modest weight loss can improve glycaemic control. However, monitor blood glucose closely during the titration phase as appetite changes may affect carbohydrate intake.

What makes GLP‑1 drugs like Wegovy more effective than Mysimba?

GLP‑1 analogues act directly on the gut‑brain axis, slowing gastric emptying and enhancing satiety hormones. This dual peripheral‑central effect yields higher average weight loss (≈15%) compared to the 5‑10% seen with Mysimba, which primarily targets central reward pathways.

Do I need to stop Mysimba before surgery?

Guidelines recommend discontinuing Mysimba at least 48hours before any elective surgery to avoid potential blood‑pressure spikes and interference with anesthesia.

How does the cost of Mysimba compare to Wegovy in Australia?

Mysimba averages AU$150‑180 per month, while Wegovy can exceed AU$560 per month. Insurance schemes occasionally cover Wegovy for severe obesity, but out‑of‑pocket expenses are considerably higher.

Can I take Mysimba while pregnant or breastfeeding?

Both naltrexone and bupropion are contraindicated during pregnancy and lactation due to insufficient safety data. Discuss alternative weight‑management strategies with your obstetrician.