Treatment of Hyperglycemia with Tirzepatide

Introduction to Tirzepatide Monotherapy

The American Diabetes Association recommends using high-potency agents like GLP-1 receptor agonists or dual GIP/GLP-1 receptor agonists (tirzepatide) when A1C is ≥1.5% above goal, which applies to patients with A1C of 9% 1, 2, 3
Tirzepatide demonstrates superior glucose-lowering efficacy compared to traditional first-line agents, with clinical trials showing A1C reductions of 2.1-2.4% when added to insulin therapy, suggesting even greater reductions as monotherapy in treatment-naïve patients 1, 2, 3

Current guidelines support using high-potency agents like GLP-1 receptor agonists or dual GIP/GLP-1 receptor agonists (tirzepatide) when A1C is ≥1.5% above goal, which applies to this patient with A1C of 9% 1, 2, 3
The 2025 ADA Standards of Care explicitly state that people with poorly managed hyperglycemia can be effectively treated with GLP-1 RA or dual GIP and GLP-1 RA (tirzepatide), even when A1C is >10% 2, 3

Traditional practice recommends insulin for patients presenting with blood glucose ≥300 mg/dL or A1C >10%, especially with catabolic features, however recent evidence demonstrates that tirzepatide can effectively manage severe hyperglycemia without insulin 1, 2, 3
Rule out type 1 diabetes before proceeding with tirzepatide monotherapy, as insulin would be mandatory in that scenario 1

Assess renal function before starting and monitor periodically, as GLP-1-based therapies are renally cleared 4
Monitor for hypoglycemia, though risk is substantially lower than with insulin or sulfonylureas 2, 3
Provide diabetes self-management education including recognition of hyperglycemia symptoms and sick day management 1

Do not delay treatment by insisting on metformin first when the patient is only willing to take tirzepatide; the A1C of 9% requires prompt, effective intervention, and tirzepatide monotherapy is guideline-supported and highly effective 1, 2, 3
Do not combine tirzepatide with DPP-4 inhibitors, as there is no added glucose-lowering benefit beyond tirzepatide alone 1
Avoid therapeutic inertia—if A1C remains ≥1.5% above goal after 3 months on maximum-tolerated tirzepatide dose, consider adding metformin or SGLT2 inhibitor rather than switching to insulin if patient remains resistant 1, 2