MOUNJARO (tirzepatide injection) is indicated for once-weekly administration as an adjunct to diet and exercise to improve glycemic control for the treatment of adult patients with type 2 diabetes mellitus.
About this page. This page summarizes information from Health Canada's product monograph for Mounjaro on adverse reactions, warnings, and special populations. It is for informational purposes only and is not a substitute for advice from your prescriber or pharmacist. Always discuss side effects and warnings with your healthcare provider. Read our full medical disclaimer →
Investigations
General disorders and administration site conditions
Gastrointestinal disorders
No clinical trials in pregnant women have been conducted. Studies in animals (i.e., rats and rabbits) have shown reproductive and developmental toxicity, including harm to fetal development and maternal weight loss. MOUNJARO is contraindicated during pregnancy. If a patient wishes to become pregnant, MOUNJARO should be discontinued at least 1 month before a planned pregnancy due to the long half-life of MOUNJARO.[7]Section 7.1.1, page 10
In a 5 mg single-dose clinical lactation study, the concentration of tirzepatide in breast milk was found to be either undetectable (limit of detection in breastmilk 4 ng/mL) to very low compared to maternal administered dose and maternal plasma concentrations. There are no available data on the effects of tirzepatide on the breastfed infant, or on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for MOUNJARO and any potential adverse effects on the breastfed infant from MOUNJARO or from the underlying maternal condition.[8]Section 7.1.2, page 10
Safety and effectiveness of MOUNJARO have not been established in pediatric patients. MOUNJARO is not indicated for use in patients younger than 18 years.[9]Section 7.1.3, page 10
No dose adjustment is required in patients over 65 years of age. In clinical trials, 1539 (30.1%) MOUNJARO-treated patients were 65 years of age or older and 212 (4.1%) were 75 years of age or older at baseline. No overall differences in safety or efficacy were detected between these patients and younger patients, but greater sensitivity of some older individuals cannot be ruled out.[10]Section 7.1.4, page 10
In a clinical pharmacology study in subjects with varying degrees of hepatic impairment, no change in tirzepatide pharmacokinetics was observed. However, there is limited clinical experience in patients with mild, moderate, or severe hepatic impairment; therefore, use MOUNJARO with caution in these patient populations.[11]Section 7.1.5, page 11
In clinical trials, 2140 (39.5%) of MOUNJARO-treated patients had mild renal impairment and 393 (7.3%) had moderate renal impairment at baseline. MOUNJARO is not recommended in patients with end stage renal impairment due to very limited clinical experience with MOUNJARO in this population.[12]Section 7.1.6, page 11
MOUNJARO causes an increase in heart rate. Caution should be observed in patients who have cardiac conditions that might be worsened by an increase in heart rate. There is no therapeutic experience in patients with congestive heart failure New York Heart Association (NYHA) class IV.[4]Section 7, page 8
Patients receiving MOUNJARO in combination with an insulin secretagogue (e.g., a sulfonylurea) or insulin may have an increased risk of hypoglycemia. The risk of hypoglycemia may be lowered by a reduction in the dose of the insulin secretagogue or insulin. The use of MOUNJARO in combination with other incretin drugs (e.g., GLP-1 receptor agonists or DPP-4 inhibitors) has not been studied and MOUNJARO should not be used in combination with those drugs.[4]Section 7, page 8
Use of MOUNJARO has been associated with gastrointestinal adverse reactions, sometimes severe. MOUNJARO has not been studied in patients with severe gastrointestinal disease, including severe gastroparesis, and therefore should be used with caution in these patients. Events related to impaired gastric emptying, including severe gastroparesis, have been reported. Monitor and consider dose modification or discontinuation in patients who develop severe gastrointestinal symptoms while on treatment. Malnutrition has been reported in patients receiving MOUNJARO, including severe, serious and fatal events. Nutritional guidance and supplementation should be considered. Discontinuation should be considered for severe or persistent cases of malnutrition.[4]Section 7, page 8
Acute events of gallbladder disease such as cholelithiasis or cholecystitis have been reported in GLP-1 receptor agonist clinical trials and post-marketing. In MOUNJARO placebo-controlled trials, acute gallbladder disease was reported by 0.6% of MOUNJARO-treated patients and 0% of placebo-treated patients. Acute pancreatitis has been observed in patients treated with GLP-1 receptor agonists. In MOUNJARO clinical studies, 14 events of acute pancreatitis were confirmed by adjudication in 13 (0.2%) MOUNJARO-treated patients versus 3 events in 3 (0.1%) comparator-treated patients. If pancreatitis is suspected, MOUNJARO should be discontinued; if confirmed, MOUNJARO should not be restarted. MOUNJARO has not been evaluated in patients with a prior history of pancreatitis.[4]Section 7, page 8
Hypersensitivity reactions have been reported with MOUNJARO in clinical trials. There have been postmarketing reports of serious hypersensitivity reactions (e.g. anaphylactic reactions and angioedema) in patients treated with MOUNJARO. If hypersensitivity reactions occur, discontinue use of MOUNJARO; treat promptly per standard of care, and monitor until signs and symptoms resolve. Anaphylaxis and angioedema have been reported with GLP-1 receptor agonists. Use MOUNJARO with caution in patients with a history of angioedema or anaphylaxis with a GLP-1 receptor agonist or related products.[5]Section 7, page 9
Rapid improvement in glucose control has been associated with a temporary worsening of diabetic retinopathy. MOUNJARO has not been studied in patients with non-proliferative diabetic retinopathy requiring acute therapy, proliferative diabetic retinopathy, or diabetic macular edema, and should be used with caution in these patients, with appropriate monitoring.[5]Section 7, page 9
MOUNJARO delays gastric emptying. Pulmonary aspiration has been reported in patients receiving long-acting GLP-1 receptor agonists undergoing general anesthesia or deep sedation. For the safe management of patients, consider the benefits and risks, and advise patients of these, prior to such procedures.[5]Section 7, page 9
Monitor patients treated with MOUNJARO for the emergence or worsening of depression, suicidal thoughts or behaviours, and/or any unusual changes in mood or behaviour. Consider the benefits and risks to individual patients prior to initiating or continuing therapy in patients with suicidal thoughts or behaviours, or those who have a history of suicidal attempts.[5]Section 7, page 9
MOUNJARO has been associated with gastrointestinal adverse reactions, which include nausea, vomiting, and diarrhea. These events may lead to dehydration, which could cause a deterioration in renal function including acute renal failure. There have been post-marketing reports of acute kidney injury and worsening of chronic renal failure, which may sometimes require hemodialysis. Monitor renal function when initiating or escalating doses of MOUNJARO in patients reporting severe adverse gastrointestinal reactions.[5]Section 7, page 9
The following additional adverse reactions have been reported during post-approval use of MOUNJARO: gastrointestinal disorders — ileus; immune system disorders — anaphylactic reaction; nervous system disorders — dysesthesia; skin and subcutaneous tissue disorders — angioedema; renal — acute kidney injury. Because these events are reported voluntarily from a population of uncertain size, it is generally not possible to reliably estimate their frequency or establish a causal relationship to drug exposure.[3]Section 8.5, page 15
Side effects and warnings must be assessed in the context of your personal health history. Discuss any concerns about adverse reactions with your prescriber or pharmacist. Use our pharmacy comparison tool to find and connect with a Canadian pharmacy that carries Mounjaro.
Last reviewed May 14, 2026 against the Health Canada Product Monograph dated April 2, 2026. View monograph →