Naltrexone in the Treatment of Ketamine Use Disorders: A Case Report and Literature Review

Nonprescribed use of ketamine has increased worldwide due to its hallucinogenic and psychedelic effects. Ketamine use disorders (KUDs) are marked by intense cravings and tolerance, which often trigger relapses and worsen recovery outcomes, defined as sustained ketamine abstinence with reduced cravings, resolved withdrawal symptoms, and improved psychosocial functioning. Currently, there are no approved pharmacological treatments for KUDs. This report examines the off-label use of naltrexone in a patient with KUDs.

The case was a 25-year-old woman diagnosed with KUDs enrolled in an outpatient, specialist addiction service. The patient presented with ketamine daily use and intense cravings when trying to stop. The patient was prescribed oral naltrexone at the initial dose of 25 mg/day, which was increased to 50 mg/day after 7 days. After the initiation of treatment, the patient experienced a marked reduction in ketamine cravings. She was able to maintain abstinence and to progress in her recovery. The positive response to naltrexone suggests its potential as an effective intervention for managing KUDs.

Our findings are consistent with 2 prior reports that have highlighted the use of naltrexone in KUDs. The 2 previous case reports indicated that naltrexone at the dosage of 50 mg/day successfully helped the patients to achieve abstinence. Studies have shown that naltrexone reduces the antidepressant effects of ketamine in treatment-resistant depression, indicating an overlap between the opioid system and ketamine's NMDA receptor activity. Larger, double-blind studies are needed to evaluate naltrexone's efficacy, safety, and optimal dosing for KUDs.