Dual Glucagon-Like Peptide-1 (GLP-1) and Glucose-Dependent Insulinotropic Polypeptide (GIP) Receptor Agonist-Associated Thyroiditis: A Case Report of Thyroid Dysfunction Following Tirzepatide Use.

Drug-induced thyroiditis is an uncommon but clinically important condition. As dual glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptor agonists like tirzepatide are increasingly used for weight management and blood sugar control, there is growing interest in understanding their potential thyroid-related effects. We report a 32-year-old woman with no personal or family history of thyroid disease who developed painless biphasic thyroiditis, initial thyrotoxicosis followed by transient hypothyroidism, after two months of tirzepatide therapy. Thyroid autoantibodies were negative, and ultrasound showed heterogeneous echotexture with increased vascularity, consistent with thyroiditis. Infectious, autoimmune, postpartum, and infiltrative causes were excluded based on clinical history, laboratory findings, and imaging. Thyroid function normalized two months after discontinuing tirzepatide without the need for treatment. This case highlights a possible association between tirzepatide and drug-induced painless thyroiditis. It adds to the limited literature and emphasizes the need for clinician awareness of this possible adverse effect.