What is Mounjaro? Mounjaro is a medication designed for weight loss and weight maintenance that contains the active ingredient Tirzepatide. Tirzepatide is a long-acting dual GIP and GLP-1 receptor agonist, targeting receptors present in the pancreatic α and β endocrine cells, the heart, vasculature, immune cells (leukocytes), gut, kidney, and adipocytes. Both GIP and GLP-1 receptors are also found in regions of the brain responsible for appetite regulation. Tirzepatide exhibits a high selectivity and affinity for human GIP and GLP-1 receptors, with its effect on the GIP receptor resembling that of the native GIP hormone, while its effect on the GLP-1 receptor is comparatively lower than that of the native GLP-1 hormone.
Mounjaro helps manage weight by acting on brain receptors that control appetite, reducing feelings of hunger and cravings. This leads to a decrease in food intake, aiding in weight loss. Mounjaro should be used in conjunction with a reduced-calorie diet and increased physical activity for optimal results.
Inclusion Criteria:
Mounjaro is indicated as an adjunct to a reduced-calorie diet and increased physical activity for weight management, including both weight loss and maintenance, in adults with an initial Body Mass Index (BMI) of:
≥ 30 kg/m² (obesity), or
≥ 27 kg/m² and < 30 kg/m² (overweight), with at least one weight-related comorbidity such as dysglycaemia (pre-diabetes or type 2 diabetes mellitus), hypertension, dyslipidaemia, or obstructive sleep apnoea.
Additional Criteria:
Age 18–75 years.
If patients have been unable to lose at least 5% of their initial body weight after 6 months of treatment, a decision must be made regarding whether to continue treatment, based on the individual patient's benefit/risk profile.
Dosage Schedule:
The starting dose of Tirzepatide is 2.5 mg, administered once weekly.
After 4 weeks, the dose should be increased to 5 mg once weekly.
Further dose increases can be made in increments of 2.5 mg, after a minimum of 4 weeks on the current dose.
The recommended maintenance doses are 5 mg, 10 mg, and 15 mg.
The maximum allowable dose is 15 mg once weekly.
Method of Administration:
Mounjaro is administered once weekly at any time of day, with or without food.
The injection should be given subcutaneously in the abdomen, thigh, or upper arm. Injection sites should be rotated.
Mounjaro should not be administered intravenously or intramuscularly.
The weekly administration day can be changed if necessary, provided there is at least a 3-day gap (>72 hours) between doses. After selecting a new dosing day, once-weekly dosing should continue.
Patients should carefully review the instructions for use in the package leaflet before administering the medication.
Red flags, exclusion and/or referral criterion:
Individuals with a BMI <30 kg/m² or <27 kg/m² with additional risk factors such as type 2 diabetes, hypertension, or hypercholesterolemia.
Pregnancy or breastfeeding.
Renal or hepatic impairment.
Allergy to any GLP-1 receptor agonists (e.g., Exenatide, Lixisenatide, Dulaglutide, Tirzepatide, Liraglutide).
History of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia type 2 (MEN 2).
Prior serious hypersensitivity reactions to liraglutide or any product component.
Type 1 diabetes or insulin-dependent diabetes.
History of depressive thoughts with suicidal ideations.
Personal or family history of thyroid cancer.
Previous episodes of pancreatitis.
History of gallstones, eating disorders, alcoholism, hypertriglyceridemia, hepatic or renal dysfunction, or gastroparesis.
Age under 18 or over 75 years.
Patient counselling:
Tirzepatide should be used in conjunction with a healthy, balanced diet and regular physical activity.
Tirzepatide should be injected at the same time each week and can be administered either before or after meals.
Injections should be administered in the upper thigh, upper arm, or abdomen (around the umbilical region), with rotation of injection sites.
The weekly injection day may be changed if necessary, as long as there is a gap of at least 3 days between doses. After choosing a new injection day, continue the once-weekly dosing schedule.
Special Warnings and Precautions for Use:
Gastrointestinal Effects: Tirzepatide can cause gastrointestinal adverse reactions that may lead to dehydration, which, in rare cases, can impair renal function. Patients should be advised of this risk and take appropriate measures to prevent fluid depletion.
Acute Pancreatitis: GIP/GLP-1 receptor agonists have been associated with acute pancreatitis. Patients should be informed about the signs and symptoms of pancreatitis. If pancreatitis is suspected, Tirzepatide should be discontinued immediately and not restarted if confirmed. Caution is advised in patients with a history of pancreatitis.
Diabetes Management: Tirzepatide should not be used as a substitute for insulin. When used with insulin or sulfonylureas, there is an increased risk of hypoglycaemia. The dose of insulin or sulfonylurea may need to be reduced when initiating Tirzepatide. The addition of Tirzepatide 2.4 mg in insulin-treated patients has not been evaluated.
Diabetic Retinopathy: Rapid improvement in glucose control may temporarily worsen diabetic retinopathy. Patients with diabetic retinopathy should be closely monitored and treated per clinical guidelines. There is limited experience with Tirzepatide 2.4 mg in patients with uncontrolled or potentially unstable diabetic retinopathy.
Sodium Content: This medication contains less than 1 mmol (23 mg) of sodium per dose, which is essentially "sodium-free."
Interaction with Other Medications:
Gastric Emptying: Tirzepatide may delay gastric emptying and potentially affect the absorption of co-administered oral medications. No clinically significant effect on gastric emptying or drug-drug interactions has been observed in clinical trials.
Oral Contraceptives: Tirzepatide does not directly reduce the effectiveness of oral contraceptives. However, it may pose a risk to pregnancy or reduce effectiveness due to gastrointestinal side effects such as vomiting and diarrhoea, so caution is advised. When co-administered with oral contraceptives containing 0.03 mg ethinylestradiol and 0.15 mg levonorgestrel, no clinically relevant changes in exposure were observed. However, levonorgestrel exposure increased by 20%.
