How should Mounjaro (tirzepatide) be managed in patients post-surgery?

Perioperative Management of Tirzepatide (Mounjaro) in Surgical Patients

Tirzepatide (Mounjaro) should be discontinued prior to elective surgery due to its effects on gastric emptying, with weekly injections stopped at least one week before the procedure to minimize aspiration risk.1

Preoperative Management

• Tirzepatide, as a dual GIP/GLP-1 receptor agonist, significantly delays gastric emptying, which increases the risk of pulmonary aspiration during anesthesia induction 1
• For elective surgeries, weekly tirzepatide injections should be discontinued at least one week before the procedure 1
• The elimination half-life of tirzepatide is approximately 5 days, making the one-week discontinuation period appropriate for drug clearance 1
• Patients should be monitored for potential hyperglycemia after discontinuation, especially those with poorly controlled diabetes 1

Intraoperative Considerations

• Blood glucose monitoring should be performed regularly during surgery, with a target of <180 mg/dL (10 mmol/L) 1
• If hyperglycemia occurs intraoperatively, consider intravenous insulin therapy using ultra-rapid insulin at a concentration of 1 IU/mL 1
• Always include simultaneous glucose infusion (100-150 g/day) with insulin therapy except in cases of significant hyperglycemia 1
• Measure blood glucose every 1-2 hours during surgery and adjust insulin rates accordingly 1

Postoperative Management

Immediate Postoperative Period

• Continue regular blood glucose monitoring in the recovery period to detect both hyperglycemia and hypoglycemia 1
• For patients with blood glucose >180 mg/dL (10 mmol/L), initiate insulin therapy using a basal-bolus regimen 2
• If transitioning from IV insulin: use half of the total 24-hour IV insulin dose as basal insulin, and divide the other half into three doses for mealtime bolus insulin 2
• Monitor for hypoglycemia (<3.3 mmol/L or 0.6 g/L) and treat immediately even in the absence of symptoms 1

Resuming Tirzepatide

• Tirzepatide should only be restarted when:
  1. The patient has resumed adequate oral intake 1
  2. The risk of postoperative nausea and vomiting has subsided 1
  3. The patient is hemodynamically stable 1
• When restarting, consider beginning with the previous maintenance dose rather than re-titrating from the starting dose 1
• If the patient cannot manage their medication autonomously post-surgery, implement a basal-bolus insulin regimen until they can resume self-administration 1

Special Considerations

• For urgent/emergency surgeries where tirzepatide cannot be discontinued in advance, consider the patient at high risk for aspiration and implement appropriate anesthetic precautions 1
• Prophylaxis of nausea and vomiting is essential for diabetic patients to ensure rapid resumption of feeding 1
• When using dexamethasone as an antiemetic, limit the dose to 4 mg (rather than 8 mg) to minimize hyperglycemia risk 1
• Effective pain management is crucial as poorly controlled pain can worsen hyperglycemia 1

Common Pitfalls to Avoid

• Failing to discontinue tirzepatide before elective surgery, increasing aspiration risk 1
• Inadequate glucose monitoring during the perioperative period 1
• Not accounting for the increased insulin resistance that occurs with surgical stress 2
• Delaying the resumption of appropriate glycemic control medications postoperatively, which may increase infection risk 3
• Using capillary blood glucose measurements in patients with vasoconstriction, which can overestimate blood glucose levels (use arterial or venous blood instead) 1

By following these guidelines, the perioperative management of patients on tirzepatide can be optimized to reduce complications while maintaining adequate glycemic control.