What volume of Mounjaro (tirzepatide) should a patient take weekly if they are currently taking 2mg, with a target dose of 5mg?

Tirzepatide (Mounjaro) Dosing for Patient Taking 2mg with Target Dose of 5mg

For a patient prescribed Mounjaro 5mg but currently taking 2mg, the patient should administer 0.4mL weekly from the 5mg/mL pen.

Dosing Calculation Explanation

Tirzepatide (Mounjaro) is a dual GIP and GLP-1 receptor agonist used for glycemic control in type 2 diabetes. The medication comes in single-dose prefilled pens with specific concentrations:

• The 5mg pen contains tirzepatide at a concentration of 5mg/mL
• For a patient taking 2mg dose from a 5mg/mL pen:
  • Dose calculation: 2mg ÷ 5mg/mL = 0.4mL

Administration Guidelines

• Tirzepatide is administered as a once-weekly subcutaneous injection
• The patient should use the dose dial on the pen to select 0.4mL
• The injection can be administered at any time of day, with or without meals
• The injection site should be rotated between the abdomen, thigh, or upper arm

Dose Escalation Protocol

Tirzepatide is typically initiated at a low dose and gradually increased to minimize gastrointestinal side effects 1, 2:

• Starting dose: 2.5mg once weekly for 4 weeks
• First escalation: 5mg once weekly
• Further escalations (if needed): 7.5mg, 10mg, 12.5mg, up to 15mg once weekly

The current 2mg dose appears to be part of the initial titration phase before reaching the target 5mg dose.

Clinical Considerations

• Gastrointestinal adverse events (nausea, diarrhea, decreased appetite, vomiting) are common, particularly during dose escalation 1, 3
• These side effects are typically mild to moderate and occur primarily during the dose-escalation period
• If the patient is experiencing significant GI side effects at 2mg, consider extending time at this dose before increasing to 5mg
• No dose adjustment is required for patients with mild to moderate renal impairment

Common Pitfalls to Avoid

1. Incorrect volume calculation: Always calculate based on the specific pen concentration (5mg/mL in this case)
2. Rapid dose escalation: Increasing the dose too quickly can worsen GI side effects
3. Inconsistent administration: Changing the day of weekly injection can affect efficacy and tolerability
4. Improper storage: Unused pens should be refrigerated (2-8°C); the pen in use can be stored at room temperature for up to 21 days

The patient should be advised to continue with the 0.4mL (2mg) dose until directed by their healthcare provider to increase to the full 5mg (1mL) dose based on tolerability and glycemic response.