MOUNJARO
Clinical safety rating
cautionComprehensive clinical and safety monograph for MOUNJARO (MOUNJARO).
Tirzepatide is a once-weekly dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist. It activates GIP and GLP-1 receptors, potentiating glucose-dependent insulin secretion from pancreatic beta cells, reducing glucagon secretion, slowing gastric emptying, and promoting satiety via hypothalamic appetite regulation.
| Metabolism | Undergoes proteolytic cleavage of the peptide backbone and beta-oxidation of the C20 fatty diacid moiety via multiple enzymes, including CYP450? (minimal CYP-mediated metabolism). Mainly metabolized by peptidases and fatty acid oxidation pathways. |
| Excretion | Primarily eliminated via proteolytic degradation, with the parent drug not significantly excreted renally or in feces. Small amounts of metabolites may be excreted in urine and feces. |
| Half-life | Terminal elimination half-life is approximately 5 days (range 4-6 days), supporting once-weekly dosing. Achieves steady-state after 4-5 weeks. |
| Protein binding | Highly bound to albumin (approximately 99%). |
| Volume of Distribution | Approximately 7.5 L (0.1 L/kg for a 75 kg individual). Indicates limited extravascular distribution. |
| Bioavailability | Subcutaneous: Approximately 80-95%. |
| Onset of Action | Subcutaneous: Glycemic effects observed within 1-2 weeks; maximal glucose-lowering effects typically seen by 4-8 weeks. |
| Duration of Action | Subcutaneous: Duration of action is approximately 1 week, consistent with half-life. Glycemic control maintained over the weekly dosing interval. |
| Molecular Weight | 4813.5 |
| Action Class | Dual GIP/GLP-1 Receptor Agonist |
Subcutaneous injection once weekly. Starting dose: 2.5 mg for 4 weeks, then increase to 5 mg for at least 4 weeks. For additional glycemic control, may increase in 2.5 mg increments after at least 4 weeks on current dose. Maximum dose: 15 mg once weekly.
| Dosage form | SOLUTION |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment (eGFR >=30 mL/min/1.73 m2). Not recommended in severe renal impairment (eGFR <30 mL/min/1.73 m2) or end-stage renal disease due to lack of data. |
| Liver impairment | No dose adjustment required for mild hepatic impairment (Child-Pugh Class A). Not recommended in moderate to severe hepatic impairment (Child-Pugh Class B or C) due to limited data. |
| Pediatric use | Safety and effectiveness in pediatric patients (<18 years) have not been established. No recommended dose. |
| Geriatric use | No specific dose adjustment required for elderly patients based on age alone. Use caution due to potential for renal function decline; monitor renal function. |
| 1st trimester | Limited human data; animal studies show fetal harm. Risk cannot be excluded. |
| 2nd trimester | Limited human data; animal studies show fetal harm. Risk cannot be excluded. |
| 3rd trimester | Limited human data; animal studies show fetal harm. Risk cannot be excluded. |
Clinical note
Comprehensive clinical and safety monograph for MOUNJARO (MOUNJARO).
| Placental transfer | Tirzepatide is a large peptide (MW about 4.8 kDa) that likely crosses the placenta at low levels; animal studies show transfer. |
| Breastfeeding | No human data on presence in breast milk; potential for adverse effects in infant due to known serious adverse reactions in adults. |
| Lactation Rating | L4 - Possibly Hazardous |
| Teratogenic Risk | First trimester: Based on animal studies, there is a risk of fetal harm due to drug-induced maternal weight loss and reduced food intake. No adequate human studies. Second and third trimesters: Potential risk of fetal hypoglycemia and altered fetal growth. Avoid use in all trimesters unless clearly needed. |
| Fetal Monitoring | Monitor maternal blood glucose, weight, and fetal growth via ultrasound. Assess for fetal hypoglycemia after delivery. Evaluate for maternal gastrointestinal adverse effects. |
| Fertility Effects | In animal studies, reduced fertility and increased preimplantation loss observed. Human data limited; may impair fertility due to weight loss and metabolic changes. |
■ FDA Black Box Warning
WARNING: RISK OF THYROID C-TUMORS. Tirzepatide caused dose-dependent and treatment-duration-dependent thyroid C-cell tumors (adenomas and carcinomas) in male and female rats. It is contraindicated in patients with a personal or family history of medullary thyroid carcinoma (MTC) and in patients with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).
| Common Effects | Nausea, Vomiting, Diarrhea, Decreased appetite, Constipation, Abdominal pain, Dyspepsia, Fatigue, Injection site reactions |
| Serious Effects | Pancreatitis (acute or chronic), Medullary thyroid carcinoma (C-cell tumors, seen in animal studies; contraindicated in patients with personal or family history of MTC or MEN-2), Severe hypoglycemia (especially when used with insulin or sulfonylureas), Acute kidney injury (often due to volume depletion from GI effects), Diabetic retinopathy complications (associated with rapid glycemic improvement), Hypersensitivity reactions (angioedema, anaphylaxis), Cholelithiasis and cholecystitis |
Personal or family history of medullary thyroid carcinomaMultiple endocrine neoplasia syndrome type 2
| Precautions | Pancreatitis (acute, hemorrhagic, necrotizing); hypoglycemia, especially with sulfonylureas or insulin; acute kidney injury; diabetic retinopathy complications in type 2 diabetes (with rapid improvement in glucose control); hypersensitivity reactions (angioedema, anaphylaxis); gallbladder disease (cholelithiasis, cholecystitis); severe gastrointestinal adverse reactions; increased heart rate; suicidal behavior or ideation; acute pancreatitis; thyroid C-cell tumors; pulmonary aspiration during general anesthesia due to delayed gastric emptying. |
| Food/Dietary | No specific food restrictions. However, high-fat, high-calorie meals may exacerbate GI side effects (nausea, delayed gastric emptying). Alcohol consumption is not known to interact, but may increase risk of hypoglycemia when combined with other antidiabetic agents. Maintain adequate fluid intake to prevent dehydration if vomiting/diarrhea occur. |
| Clinical Pearls | MOUNJARO (tirzepatide) is a once-weekly GIP/GLP-1 receptor agonist. Initiate at 2.5 mg for 4 weeks, then increase by 2.5 mg every 4 weeks to a max of 15 mg. Dose escalation mitigates GI side effects. Contraindicated in patients with a personal/family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN-2). Monitor for pancreatitis, gallbladder disease, and hypoglycemia when used with insulin secretagogues. Consider temporary discontinuation prior to surgery due to delayed gastric emptying. |
| Patient Advice | Administer once weekly, on the same day each week, with or without meals. Rotate injection sites (abdomen, thigh, upper arm). · If a dose is missed and it has been ≤4 days, administer as soon as possible; if >4 days, skip the missed dose and resume the regular schedule. · Common side effects include nausea, vomiting, diarrhea, and constipation; these often improve over time. Eat smaller, low-fat meals and avoid high-fat or spicy foods to reduce GI symptoms. · Seek medical attention for severe abdominal pain (possible pancreatitis), persistent vomiting/diarrhea (risk of dehydration), or symptoms of hypoglycemia (dizziness, sweating, confusion) especially if taking insulin or sulfonylureas. · Inform all healthcare providers you are taking MOUNJARO, especially before any surgical procedures or imaging studies. · Report any lump in the neck, hoarseness, or trouble swallowing (signs of thyroid tumors). |
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