Hepatic Safety of Ketamine and Esketamine for Treatment-Resistant Depression

BACKGROUND: Ketamine and esketamine are increasingly used for treatment-resistant depression (TRD), yet their hepatic safety profile with repeated or long-term use remains poorly characterized. Chronic recreational ketamine abuse has been linked to cholestasis and cholangiopathy, raising concern that therapeutic use may carry similar risks. No systematic data exist on liver enzyme trajectories or biliary injury at subanesthetic doses used for depression. METHODS: This historical cohort study included adults with TRD receiving IV ketamine or intranasal (IN) esketamine at the Mayo Clinic Ketamine Clinic (2017 to 2024). Patients were eligible if they had at least one liver enzyme value (AST, ALT, ALP, or bilirubin) within 12 months before through 3 months after treatment. Longitudinal enzyme trajectories were modeled using generalized linear-mixed models with a Gamma distribution. Clinically significant elevation was defined as ≥2× the upper limit of normal (ULN). Wilcoxon signed-rank tests compared pretreatment and post-treatment paired values. RESULTS: Of 104 enrolled patients, 74 had liver enzyme data available; 51 had post-initiation data. Median age was 51.5 years; 72% were female. Most (78.4%) received IV ketamine. No clinically meaningful changes in enzyme trajectories were observed. Three patients (5.9%) had elevations ≥2× ULN, all attributable to alcohol use, myalgias, or pre-existing hepatic steatosis rather than (es)ketamine. CONCLUSIONS: Subanesthetic IV ketamine (0.5 mg/kg) and FDA-approved IN esketamine doses were not associated with clinically significant liver enzyme elevations in this real-world TRD cohort. Current evidence does not support routine hepatic monitoring for asymptomatic patients, although prospective, larger-scale studies are needed to confirm these findings.