What dose of Mounjaro (tirzepatide) can a patient on Ozempic (semaglutide) 2 mg be switched to?

Switching from Ozempic 2 mg to Mounjaro: Dosing Recommendations

For a patient on Ozempic (semaglutide) 2 mg weekly, switching to Mounjaro (tirzepatide) 10 mg weekly is the most appropriate conversion dose.

Rationale for Dose Selection

When transitioning from semaglutide 2 mg to tirzepatide, several factors must be considered:

1. Pharmacological differences:

   • Tirzepatide is a dual GIP/GLP-1 receptor agonist, while semaglutide is a GLP-1 receptor agonist only
   • Both medications have similar half-lives (approximately 5 days for tirzepatide vs. 7 days for semaglutide) 1
   • Both are administered subcutaneously once weekly

2. Relative potency:

   • Tirzepatide has demonstrated greater efficacy for both glycemic control and weight reduction compared to semaglutide at comparable doses 2, 3
   • In comparative studies, tirzepatide 10-15 mg shows superior outcomes to semaglutide 1-2.4 mg 4

3. Dosing considerations:

   • Ozempic 2 mg is a high-dose GLP-1 RA formulation
   • Mounjaro is available in 5 mg, 10 mg, and 15 mg doses
   • Starting with tirzepatide 10 mg provides a balanced approach between efficacy and tolerability

Dosing Algorithm

1. For patients on Ozempic 2 mg weekly:

   • Initial conversion: Start with Mounjaro 10 mg weekly
   • Titration option: May increase to 15 mg after 4 weeks if additional glycemic control or weight loss is needed
   • Alternative for sensitive patients: Start with 5 mg if concerned about GI tolerability, then titrate to 10 mg after 4 weeks

2. Administration timing:

   • Administer the first dose of tirzepatide one week after the last dose of semaglutide
   • Maintain the same day of the week for administration if possible

Safety Considerations

• Gastrointestinal side effects: Both medications commonly cause GI effects, but tirzepatide may have a higher incidence, particularly at higher doses 2, 4

• Monitoring recommendations:

  • Monitor blood glucose more closely during the first 4 weeks of therapy
  • If patient is on sulfonylureas, consider reducing dose by 50% when initiating tirzepatide
  • If on insulin, consider reducing basal insulin dose by 20% 5

• Contraindications (applicable to both medications):

  • Personal or family history of medullary thyroid carcinoma
  • Multiple Endocrine Neoplasia syndrome type 2
  • Pregnancy or breastfeeding
  • History of severe hypersensitivity to either drug 5

Evidence for Superiority

Recent comparative studies show tirzepatide provides:

• Greater HbA1c reduction compared to equivalent semaglutide doses 2
• Superior weight loss outcomes (20.2% vs 13.7% in direct comparison studies) 3
• Potentially greater cardiovascular benefit (HR 0.86; 95% CI 0.74-0.99 compared to semaglutide) 6

Clinical Pearls

• Both medications have similar renal considerations - no dose adjustment is required for tirzepatide or semaglutide with eGFR ≥30 mL/min/1.73m² 5

• Tirzepatide may require more careful dose titration due to potentially stronger GI side effects

• Consider the patient's primary treatment goal (glycemic control vs. weight loss) when determining the optimal dose, as tirzepatide 15 mg provides maximal weight loss benefit but with potentially more side effects 4

• Both medications have similar black box warnings regarding thyroid C-cell tumors in rodents 1