| name | mounjaro-prescribing-guide |
| description | Bedside prescribing reference for Mounjaro (tirzepatide) — indications, dose escalation, missed-dose rule, KwikPen vs prefilled pen differences, contraindications, warnings, storage, and monitoring. Use when a clinician asks how to start tirzepatide, how to titrate Mounjaro, how to handle a missed weekly dose, Mounjaro storage, Mounjaro contraindications, Mounjaro pregnancy/MTC warnings, or needs a quick Mounjaro monograph lookup. Grounded in the Canadian Product Monograph (Eli Lilly Canada, April 2026). |
Mounjaro (Tirzepatide) — Prescribing Guide
Indication
Adjunct to diet and exercise for glycemic control in adult T2D.
- Monotherapy (if metformin inappropriate)
- With metformin ± SU, with metformin ± SGLT2i, or with basal insulin ± metformin
- Not for T1D, DKA, combination with short/medium-acting or dual insulin
- Not indicated for pediatrics (< 18 y)
Contraindications
- Personal/family history of MTC or MEN-2
- Pregnancy (contraindicated)
- Hypersensitivity to tirzepatide or excipients (incl. benzyl alcohol in KwikPen)
Dose Escalation
| Step | Dose | Minimum duration |
|---|
| Start | 2.5 mg s.c. once weekly | 4 weeks (initiation — not for glycemic control) |
| Step up | 5 mg weekly | ≥ 4 weeks |
| Further | +2.5 mg every ≥ 4 weeks | as needed |
| Max | 15 mg weekly | — |
- Any day, any time, with or without meals.
- Inject abdomen, thigh, or upper arm — rotate sites.
- Never IM or IV; never mix with insulin (separate injections).
- No dose adjustment for renal or hepatic impairment or age ≥ 65. Not recommended in ESRD.
Missed Dose
- Within 4 days (96 h) of missed dose → administer ASAP; resume schedule.
- > 4 days → skip; resume on regularly scheduled day.
- To change weekly day: ≥ 72 h must separate two doses.
KwikPen vs Single-Dose Pen/Vial
| Feature | Single-dose pen/vial | KwikPen (multi-dose) |
|---|
| Doses per device | 1 | 4 |
| Preservative | None | Benzyl alcohol 5.4 mg/0.6 mL + phenol |
| Monthly devices | 4 | 1 |
| Discard after | Single use | 4 weekly doses |
| Unrefrigerated storage | Up to 21 days at ≤ 30°C | Up to 30 days at ≤ 30°C |
Hepatic or renal impairment + KwikPen: inform patient of metabolic acidosis risk from benzyl alcohol accumulation — prefer single-dose if concerned.
Storage
- Refrigerate 2–8°C until expiry.
- Do not freeze. If frozen → discard.
- Protect from light (original carton).
- Discard used pens in puncture-resistant container.
Key Warnings
- Thyroid C-cell tumours (black-box): counsel on neck mass, dysphagia, dyspnea, hoarseness. Routine calcitonin/US monitoring not recommended.
- Gastrointestinal AEs (see
glp1-gi-ae-symptom-advisor + glp1-dose-escalation-troubleshooter).
- Severe gastroparesis — not studied; caution / consider dose modification / discontinuation.
- Malnutrition — reported including severe/fatal; consider nutritional supplementation; discontinue if severe/persistent.
- Acute pancreatitis (0.2% in trials) — see
glp1-pancreatobiliary-risk-monitor. Not evaluated in prior AP — caution.
- Acute gallbladder disease (0.6%) — cholelithiasis/cholecystitis/cholecystectomy.
- Acute kidney injury via dehydration from GI AEs — monitor renal function during dose escalation if severe GI reactions.
- Diabetic retinopathy — rapid glucose correction may transiently worsen; caution in proliferative/macular edema.
- Heart rate increase 2–4 bpm mean; caution in patients where HR rise could worsen cardiac status. No NYHA IV experience.
- Pulmonary aspiration under GA / deep sedation — see
glp1-perioperative-aspiration.
- Suicidal ideation — monitor for mood changes.
- Hypersensitivity / anaphylaxis / angioedema — discontinue if occurs.
Monitoring
- HbA1c for long-term glycemic response.
- Self-monitored glucose only needed when combined with SU/insulin.
- Monitor renal function if severe GI AEs with dehydration.
- Refer to endocrinology if thyroid nodules found incidentally or serum calcitonin elevated.
Special Populations
- Elderly ≥ 65: no dose adjustment; 30% of trial pop was ≥ 65, 4% ≥ 75.
- Pregnancy: contraindicated. Discontinue ≥ 1 month before planned pregnancy (long half-life ~5 days).
- Breastfeeding: very low milk transfer; individualise risk/benefit.
- Oral contraceptives: reduced absorption — use non-oral contraception or add barrier method for 4 weeks after initiation AND for 4 weeks after each dose escalation. See
glp1-oral-contraceptive-interaction.
Drug Combinations Requiring Dose Reduction
- Sulfonylurea / basal insulin → reduce dose to lower hypoglycemia risk (trial reduced baseline insulin by 20%). See
glp1-insulin-su-dose-reduction.
- Other incretin drugs (GLP-1 RA, DPP-4i) → do not combine.
Overdose
Expected symptom: GI (nausea). Supportive care; prolonged observation due to long half-life.
Reference
MOUNJARO Product Monograph, Eli Lilly Canada, authorised 2026-04-02. Control #301221.
