A 66-year-old woman developed rhabdomyolysis — a potentially dangerous breakdown of muscle tissue — after receiving an increased dose of tirzepatide, recovering within 4 days of stopping the drug.
First reported caseThis is the first documented case of rhabdomyolysis associated with tirzepatide, a widely prescribed GLP-1/GIP agonist
What the researchers found
A 66-year-old woman developed rhabdomyolysis with markedly elevated creatine kinase levels following her first administration of an increased dose of tirzepatide. The temporal relationship between drug initiation and symptom onset strongly suggested tirzepatide as the trigger. Laboratory findings normalized within 4 days of drug discontinuation and supportive IV fluid therapy. The authors report this as the first documented case of rhabdomyolysis associated with tirzepatide.
Why it matters
Tirzepatide (Mounjaro/Zepbound) is one of the most widely prescribed new medications globally, used for both type 2 diabetes and weight loss. Identifying rare but serious adverse effects like rhabdomyolysis is critical for patient safety, especially given the widespread off-label use of this drug class for weight management.
How the study worked
This is a single-patient case report documenting the clinical presentation, laboratory findings, treatment, and outcome of rhabdomyolysis temporally associated with tirzepatide administration. The causality assessment was based on the temporal relationship and recovery after discontinuation.
What this study cannot tell us
As a single case report, this represents the lowest level of clinical evidence. A causal relationship cannot be definitively established — the temporal association is suggestive but not conclusive. No rechallenge was performed, and other potential contributing factors may not have been fully excluded.
How to read the evidence
This is a single case report — the lowest tier of clinical evidence. It raises an important safety signal but cannot establish causation or estimate the frequency of this adverse event.
When this study was published
Published in 2025, this is a very recent pharmacovigilance report relevant to one of the most widely prescribed new medications globally.
The bigger picture
GLP-1 and dual GLP-1/GIP receptor agonists are experiencing explosive growth in prescriptions worldwide. As millions more patients use these drugs — many off-label for weight loss — rare adverse events that weren't captured in clinical trials are beginning to emerge. This case highlights the importance of post-marketing surveillance for this drug class.
Questions still open
- Is rhabdomyolysis a class effect of GLP-1 receptor agonists, or specific to tirzepatide?
- Does dose escalation speed play a role in triggering this adverse event?
- How frequently does subclinical muscle injury occur with tirzepatide that goes undetected?
Common questions
What is rhabdomyolysis and why is it dangerous?
Should I stop taking tirzepatide because of this report?
Read the original research
Case Report: Rhabdomyolysis following initiation of tirzepatide.
Frontiers in pharmacology, 16, 1660785
Citation
Bodanowitz, Jonas Michael; Mattes, Isabell; Loebermann, Micha; Fritzsche, Carlos. (2025). Case Report: Rhabdomyolysis following initiation of tirzepatide.. Frontiers in pharmacology, 16, 1660785. https://doi.org/10.3389/fphar.2025.1660785