What is the recommended starting dose of Mounjaro (tirzepatide)?

Mounjaro Starting Dose

The recommended starting dose of Mounjaro (tirzepatide) is 2.5 mg administered subcutaneously once weekly for the first 4 weeks. 1

Initial Dosing Protocol

• Start with 2.5 mg subcutaneously once weekly for 4 weeks as the initial dose, which serves as a dose-escalation period rather than a therapeutic dose 1
• After completing 4 weeks at 2.5 mg, increase to 5 mg once weekly, which represents the first maintenance dose 1
• The medication can be administered at any time of day, with or without meals 1

Dose Escalation Strategy

Following the initial 4-week period at 2.5 mg and subsequent increase to 5 mg:

• Increase to 10 mg once weekly after at least 4 weeks on the 5 mg dose if additional glycemic control or weight loss is needed 1
• Maximum dose is 15 mg once weekly, which can be reached after at least 4 weeks on the 10 mg dose 1
• All dose escalations should occur in 4-week intervals minimum to allow for tolerability assessment 1

Administration Considerations

• No dose adjustments are required for renal impairment, making initiation straightforward in patients with kidney disease 1
• The 2.5 mg starting dose is critical for minimizing gastrointestinal side effects, which are dose-dependent and occur in 39-49% of patients depending on final dose 2
• Nausea (10-31%) and diarrhea (7-23%) are the most common adverse effects, typically mild to moderate, and decrease over time with continued use 1, 2

Important Safety Monitoring

• Monitor for signs of pancreatitis (severe epigastric pain, nausea, vomiting) and discontinue immediately if suspected, as acute pancreatitis can occur though rates are low (≤1%) 1, 2
• Contraindicated in patients with personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia type 2 due to black box warning regarding thyroid C-cell tumors in rodents 1
• Use caution when initiating or escalating doses in patients with kidney disease due to potential risk of acute kidney injury from gastrointestinal fluid losses 1

Common Pitfall to Avoid

The most critical error is starting at a higher dose than 2.5 mg. The 2.5 mg starting dose is not optional—it is essential for tolerability. Studies show that drug discontinuation rates increase with higher doses (4.3% at 5 mg, 7.1% at 10 mg, and 6.2% at 15 mg), emphasizing the importance of gradual titration 3, 2. Skipping the initial 2.5 mg dose significantly increases the risk of intolerable gastrointestinal side effects leading to treatment discontinuation.