Tirzepatide (Mounjaro) Dosing and Treatment Plan for Weight Loss
For weight loss, tirzepatide (Mounjaro) should be initiated at a low dose and gradually increased to a target dose of 10-15 mg weekly, with monitoring for efficacy and side effects at least monthly for the first 3 months and quarterly thereafter. 1
Dosing Protocol
- Start with a low dose and gradually increase to minimize gastrointestinal side effects 2, 1
- Recommended maintenance doses for weight loss are 10 mg or 15 mg once weekly, which have demonstrated superior weight loss outcomes 2, 3
- The 15 mg weekly dose provides the maximum weight loss benefit, with average weight reductions of 20.9% from baseline after 72 weeks of treatment 4
- Tirzepatide is administered as a subcutaneous injection once weekly 2
Efficacy Assessment and Treatment Duration
- Assess efficacy at least monthly for the first 3 months and at least quarterly thereafter 1
- If insufficient weight loss is achieved (<5% weight loss after 3 months), consider discontinuing the medication and exploring other treatment options 2, 1
- For optimal results, treatment should continue for at least 72 weeks (approximately 1.5 years) based on clinical trials 4
- Long-term treatment (up to 3 years) has shown sustained weight reduction benefits 5
Expected Outcomes
- At 72 weeks, patients can expect:
- 15.0% weight loss with 5 mg weekly dose
- 19.5% weight loss with 10 mg weekly dose
- 20.9% weight loss with 15 mg weekly dose 4
- 91% of patients on the 15 mg dose achieve at least 5% weight loss 4
- 57% of patients on the 15 mg dose achieve 20% or greater weight loss 4
- Tirzepatide produces superior weight loss compared to semaglutide (20.2% vs. 13.7% at 72 weeks) 3
Side Effects and Monitoring
- Most common adverse events are gastrointestinal (nausea, vomiting, diarrhea), primarily occurring during dose escalation 2, 4
- Monitor for potential pancreatitis and discontinue if suspected 2, 1
- Use caution in patients with kidney disease when initiating or increasing dose due to potential risk of acute kidney injury 2, 1
- Be aware of the black box warning regarding risk of thyroid C-cell tumors in rodents (human relevance not determined) 2, 1
- Monitor for gastrointestinal disorders including severe constipation and small bowel obstruction/ileus progression 2
Important Contraindications
- Contraindicated in women who are or may become pregnant 2, 1
- Women of reproductive potential must use reliable contraception methods 1
- Advise those using oral hormonal contraception to use or add a non-oral contraception method for 4 weeks after initiation and dose escalations 2
Additional Considerations
- Monitor effects of oral medications with narrow therapeutic index (e.g., warfarin) or medications whose efficacy depends on threshold concentrations 2
- Tirzepatide not only promotes weight loss but also improves cardiometabolic measures 4
- In patients with prediabetes, tirzepatide significantly reduces the risk of progression to type 2 diabetes 5