Tirzepatide (Weight Management) (Zepbound)

1. Health Canada Product Monograph — Tirzepatide (Weight Management)

• As an adjunct to a reduced-calorie diet and increased physical activity, for chronic weight management in adults with an initial BMI of 30 kg/m2 or greater (obesity), or 27 kg/m2 or greater (overweight) in the presence of at least 1 weight-related comorbidity such as hypertension, type 2 diabetes, dyslipidemia, obstructive sleep apnea, or cardiovascular disease.
• For the treatment of moderate to severe obstructive sleep apnea in adults with obesity, as an adjunct to a reduced-calorie diet and increased physical activity.
• Do not substitute for Mounjaro (tirzepatide for type 2 diabetes) or use the two products interchangeably.

Contraindicated in pregnancy. Confirm pregnancy status and discuss alternative therapy with the prescriber before dispensing.

• Contraindicated. Discontinue at least 2 months before a planned pregnancy given the drug's long elimination half-life and the theoretical risk that treatment-related weight loss itself could harm the fetus.

• Not recommended. Tirzepatide is a large protein molecule and would be expected to transfer into breast milk only in very small amounts, but no human lactation data are available to confirm safety.

• No specific dose adjustment is required based on age alone; monitor closely for gastrointestinal adverse effects and volume status.

• Not established for use in patients under 18 years of age.

• Initiate at 2.5 mg subcutaneously once weekly for 4 weeks (this is a treatment-initiation dose, not intended for weight-loss efficacy).
• Increase to 5 mg once weekly for at least 4 weeks; if further weight loss or symptom control is needed and the dose is tolerated, increase in increments of 2.5 mg at intervals of at least 4 weeks.
• Maximum dose is 15 mg once weekly; the effective maintenance dose is individualized between 5 mg and 15 mg once weekly based on response and tolerability.
• If a dose increase is not tolerated, delay escalation to the next dose by an additional 4 weeks before trying again, or remain at the previous tolerated dose.
• Inject subcutaneously into the abdomen, thigh, or upper arm; rotate injection sites. May be administered at any time of day, on the same day each week, independent of meals.

If overdose is suspected, seek emergency medical attention immediately or contact your regional Poison Control Centre without delay.

• Overdose experience is limited; expect an increase in gastrointestinal adverse effects (nausea, vomiting) proportional to the excess dose. Manage with supportive care and monitoring for dehydration/hypoglycemia if the patient also uses insulin or a sulfonylurea.

• Nausea, vomiting, diarrhea, constipation, and injection site reactions, particularly during dose escalation, and are minimized by adhering to the recommended slow titration schedule.

Serious side effects require immediate discussion with the prescriber or emergency care.

• Acute pancreatitis — persistent severe abdominal pain, with or without radiation to the back, warrants immediate discontinuation and evaluation; do not restart if pancreatitis is confirmed.
• Cholelithiasis and cholecystitis.
• Gastroparesis and, rarely, bowel obstruction — evaluate promptly for severe abdominal distension, persistent vomiting, or absence of bowel movements/flatus.
• Acute kidney injury, usually secondary to dehydration from severe vomiting or diarrhea.
• Hypersensitivity reactions.

• History of gallbladder disease.
• Renal impairment, or any condition predisposing to volume depletion given the gastrointestinal adverse-effect profile.
• Concurrent insulin or sulfonylurea therapy — hypoglycemia risk may require a dose reduction of the concurrent agent.

• Personal or family history of medullary thyroid carcinoma.
• Multiple endocrine neoplasia syndrome type 2 (MEN 2).
• Pregnancy and breastfeeding.
• Known hypersensitivity to tirzepatide or any excipient.

• Delays gastric emptying, which can affect the rate of absorption of concurrently administered oral medications, including oral contraceptives — monitor efficacy of narrow-therapeutic-index oral drugs.
• Increased hypoglycemia risk when combined with insulin or a sulfonylurea; a dose reduction of the concurrent agent may be required.

• None specific — unlike orlistat, efficacy does not depend on meal fat content or timing relative to meals.

• Any day of the week, at any time of day; keep the same weekly day for consistency. The day can be changed if at least 3 days have elapsed since the last dose.

• Store unused pens refrigerated at 2-8°C; do not freeze. An individual pen may be kept at room temperature (below 30°C) for a limited period per the pen's own labelling — confirm the exact in-use storage duration before relying on room-temperature storage.

• This is a distinct product from the tirzepatide used for diabetes (Mounjaro) — the two must not be substituted for one another.
• Nausea is common when starting or increasing the dose and usually improves with time; report severe or persistent abdominal pain right away.
• This medication is intended for long-term, ongoing use — stopping it typically leads to weight regain.