What is the recommended initial dose of Mounjaro (tirzepatide) when transitioning from 2.5 mg of Ozempic (semaglutide)?

Transitioning from Ozempic 2.5 mg to Mounjaro

When switching from Ozempic (semaglutide) 2.5 mg to Mounjaro (tirzepatide), start Mounjaro at the standard initial dose of 2.5 mg once weekly at the time of your next scheduled Ozempic dose, with no washout period required. 1, 2

Starting Dose and Rationale

• All patients transitioning to Mounjaro must begin at 2.5 mg weekly, regardless of their previous semaglutide dose. 2
• The 2.5 mg dose is specifically for treatment initiation and is not intended for glycemic control—it serves to minimize gastrointestinal side effects. 2
• Even though you have developed tolerance to semaglutide's GI effects, tirzepatide's dual GIP/GLP-1 mechanism may cause new or different gastrointestinal side effects that require gradual titration. 1

Titration Schedule After Starting

After initiating at 2.5 mg, follow this FDA-approved escalation schedule: 2

• Week 1-4: 2.5 mg once weekly (initiation dose)
• Week 5 onward: Increase to 5 mg once weekly
• Subsequent increases: If additional glycemic control or weight loss is needed, increase in 2.5 mg increments (to 7.5 mg, 10 mg, 12.5 mg, or 15 mg) after at least 4 weeks on each dose
• Maximum dose: 15 mg once weekly 2

Timing of the Switch

• Administer the first Mounjaro dose at the time of your next scheduled Ozempic injection—no washout period is necessary. 1
• Both medications are dosed once weekly, making the transition straightforward. 1

Important Safety Considerations

Gastrointestinal Side Effects

• Expect potential nausea, vomiting, diarrhea, and esophageal reflux, which may be more pronounced with tirzepatide despite prior semaglutide use. 1
• Eat smaller portions during the titration phase to minimize GI symptoms. 1
• Nausea is typically self-limited and does not indicate gastrointestinal pathology. 1
• If treatment must be suspended and restarted, begin again at 2.5 mg with gradual up-titration to avoid recurrent symptoms. 1

Medication Adjustments

• If taking sulfonylureas: Reduce dose by 50% or discontinue entirely when starting tirzepatide to reduce hypoglycemia risk. 1
• If on insulin therapy: Decrease basal insulin by 20-30% to minimize hypoglycemia risk. 1
• Tirzepatide may delay gastric emptying, potentially affecting absorption of oral medications requiring rapid onset. 1

Contraindications and Warnings

• Do not use if you have a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2. 2
• Use caution in patients with kidney disease when initiating or increasing doses due to potential risk of acute kidney injury. 1
• Monitor for cholelithiasis and gallstone-related complications. 1

Expected Efficacy

• Tirzepatide demonstrates superior efficacy compared to semaglutide, with mean weight loss of 20.2% versus 13.7% at 72 weeks in patients with obesity. 3
• In patients with type 2 diabetes, tirzepatide 15 mg achieved greater HbA1c reduction (-2.30 percentage points) compared to semaglutide 1 mg (-1.86 percentage points). 4
• Real-world data shows mean weight loss of -17.2 kg with tirzepatide versus -14.6 kg with semaglutide 2.4 mg after 1 year. 5

Monitoring

• Assess efficacy and safety at least monthly for the first 3 months, then at least quarterly thereafter. 1
• Monitor for severe constipation and small-bowel obstruction/ileus progression. 1