Mounjaro Starter Dose
The starter dose for Mounjaro (tirzepatide) is 2.5 mg subcutaneously once weekly for 4 weeks, not 7.5 mg. 1, 2
Dosing Algorithm
Initial Dosing Phase
- Start at 2.5 mg subcutaneously once weekly for 4 weeks to minimize gastrointestinal side effects during the dose-escalation period 1, 3, 4
- After the initial 4-week period, increase to 5 mg once weekly 1, 3
Dose Escalation Strategy
- If additional glycemic control or weight loss is needed after at least 4 weeks on the 5 mg dose, escalate to 7.5 mg once weekly 1, 3
- Further escalation to 10 mg and then 15 mg (maximum dose) can occur in 4-week intervals based on clinical response and tolerability 1, 3, 4
Available Strengths
The 7.5 mg/0.5 mL pen mentioned in your question is a maintenance dose pen, not a starter dose pen 1, 2. The complete dosing range includes:
- 2.5 mg (starter dose)
- 5 mg (first maintenance dose)
- 7.5 mg (intermediate maintenance dose)
- 10 mg (higher maintenance dose)
- 15 mg (maximum dose) 1, 3, 4
Critical Safety Considerations
Gastrointestinal Effects
- The 20-week dose-escalation period in clinical trials was specifically designed to minimize gastrointestinal adverse events (nausea, vomiting, diarrhea, decreased appetite), which are the most common side effects 4
- Starting at 2.5 mg rather than jumping to 7.5 mg significantly reduces treatment discontinuation rates due to GI intolerance 4
Pancreatitis Risk
- Maintain high clinical suspicion for acute pancreatitis, particularly in patients with pre-existing gallstones or metabolic risk factors 5
- Discontinue immediately if pancreatitis is suspected, as temporal correlation between drug initiation and symptom onset has been documented 5