Mounjaro: The New Frontier in Diabetes and Weight Loss
In Australia, Mounjaro (tirzepatide) has been approved by the Therapeutic Goods Administration (TGA) for the management of both type 2 diabetes and chronic weight management. Initially introduced in 2023 for type 2 diabetes, its indication was expanded in September 2024 to include weight management for adults with obesity or overweight conditions accompanied by at least one weight-related health issue.
Mechanism of Action
Tirzepatide is a novel medication that functions as a dual agonist for glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors. By activating these receptors, it enhances insulin secretion, suppresses glucagon release, and slows gastric emptying. These combined actions lead to improved blood glucose control and reduced appetite, facilitating weight loss.
Indications in Australia
Type 2 Diabetes Mellitus: Mounjaro is indicated as an adjunct to diet and exercise for adults with insufficiently controlled type 2 diabetes, either as monotherapy or in combination with other antidiabetic agents.
Chronic Weight Management: Approved for adults with a body mass index (BMI) of ≥30 kg/m², or ≥27 kg/m² in the presence of at least one weight-related condition such as hypertension, dyslipidaemia, obstructive sleep apnoea, cardiovascular disease, or type 2 diabetes.
Common Side Effects
Patients may experience gastrointestinal symptoms, including nausea, vomiting, diarrhoea, constipation, and decreased appetite. These side effects are generally mild to moderate and tend to diminish over time.
Effectiveness
Clinical trials have demonstrated that tirzepatide significantly reduces HbA1c levels in individuals with type 2 diabetes. Additionally, it has shown substantial weight loss benefits, with some studies reporting up to a 20% reduction in body weight.
Availability and Access
Mounjaro is available in Australia; however, it is not currently subsidised under the Pharmaceutical Benefits Scheme (PBS), requiring patients to obtain it via private prescription. The medication is administered as a once-weekly subcutaneous injection, with dosages tailored to individual therapeutic needs.
Patients considering Mounjaro for diabetes management or weight loss should consult with their healthcare provider to determine its suitability and to discuss potential benefits and risks.