Rhabdomyolysis triggered by initiation of tirzepatide.

We report a case of rhabdomyolysis triggered by initiation of tirzepatide, a novel dual agonist of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors. The patient was a 68-year-old man with a medical history of type 2 diabetes mellitus (T2DM), dyslipidemia, and chronic kidney disease (CKD). After starting tirzepatide, he developed a significant elevation of creatine kinase (CK) and other muscle injury markers. These laboratory abnormalities rapidly returned to normal range after discontinuation of the drug. Based on the naranjo adverse drug reaction probability scale and the WHO-Uppsala Monitoring Centre (WHO-UMC) causality assessment system, the association between tirzepatide and rhabdomyolysis was classified as "probable." To our knowledge, no previous cases of tirzepatide-induced rhabdomyolysis for T2DM have been reported in the literature. Although this adverse effect appears to be extremely rare, it is important to monitor CK levels when initiating tirzepatide therapy. Early detection of muscle injury markers may help prevent serious complications and ensure the safe use of this novel antidiabetic agent.