Abstract
Rhabdomyolysis (RM) is characterised by the breakdown of skeletal muscle tissue, releasing toxic intracellular components into circulation. It presents with dark urine, muscle weakness, myalgia, and elevated creatine phosphokinase levels (CPK). Drug-induced RM is aetiologically significant. This case report describes a 25-year-old male who developed severe RM and Acute Kidney Injury (AKI) after intramuscular (IM) heroin administration as a first time user. IM heroin use can induce higher CPK levels due to direct myocyte toxicity and mechanical trauma. The highly vascularised gluteal muscles with type 1 fibres at the injection site likely exacerbated the severity. Additional factors included lower mitochondrial density in males and alcohol exposure. Despite aggressive fluid resuscitation, renal replacement therapy (RRT) was required, and the patient responded well to haemodialysis. This case highlights AKI as a severe complication of IM heroin use, underscoring the need for further research into drug-induced RM.