Jarka 2023: kratom withdrawal after a first naltrexone tablet for weight loss

What they tested

This case report describes a man prescribed naltrexone 50 mg once daily for weight loss, an off-label use. He had high blood pressure, sleep apnea, obesity and anxiety, and denied using drugs or misusing alcohol. His urine drug screen was negative, including for methadone, fentanyl and buprenorphine.

Only when a neurologist and pharmacist took a detailed medication history did his wife report that he mixed large amounts of kratom powder into his coffee every morning for knee pain. He later said it was about 1 tablespoon (8 g) a day, bought from a local smoke shop.

What they found

Within 30 minutes of the first tablet he felt restless, cold and sweaty, with a fast heartbeat. Within 2 hours of reaching the emergency room he was agitated, confused and hallucinating. He scored 39 on an alcohol withdrawal scale, with symptoms resembling delirium tremens.

He was admitted to intensive care and treated with a dexmedetomidine infusion and lorazepam, receiving 24 mg of lorazepam in the first 24 hours. His withdrawal lasted about 36 hours, and he went home directly from intensive care after 48 hours.

The authors rated it a probable drug reaction (Naranjo score 8). They credit oral naltrexone's short half-life for the episode not lasting longer. Afterwards he stopped both kratom and naltrexone.

Limits

• It describes one person, so it can't show how often this happens.
• His kratom use was identified from his and his wife's accounts, not a lab test.

What it means if you're considering naltrexone

The authors expect naltrexone to be used more often outside addiction treatment, for uses like weight loss, where prescribers may not think to ask about kratom. This case shows that regular kratom use can turn a first naltrexone dose into severe withdrawal, and the authors urge screening for herbal supplements before naltrexone is started.