Jensen 2021: kratom, liver inflammation and withdrawal after a naltrexone shot

What they tested

This case report describes one patient at a Veterans Affairs residential treatment program in Florida. He had a long history of drinking kratom as herbal tea, which he viewed as similar to green or chamomile tea, and asked to switch from buprenorphine/naloxone to intramuscular naltrexone, an injection into a muscle.

His team tested his urine several times for mitragynine, kratom's main compound. Results took about 2 weeks to come back. He denied using kratom until a test came back positive, then admitted he had been ordering it to the facility through a food delivery service.

What they found

On day 31 of his stay his liver enzymes were high: AST 173 U/L and ALT 586 U/L, 4 and 10 times the upper limit of normal. Tests ruled out hepatitis A, B and C and acetaminophen. His naltrexone start was put off, first because of the positive kratom test and then because of the liver results.

On day 45, with his enzymes below 10 times normal and 16 days after the last kratom use he reported, he got the injection. The next day he had nausea, vomiting, stomach pain, muscle spasms, uncontrollable jerking of his limbs and yawning. On day 47 he went to the emergency department with dehydration, vomiting and diarrhea, was given fluids and an anti-nausea drug, and went back to the program. Symptoms resolved within 72 hours of the injection.

Later kratom tests were also positive, suggesting he kept using it during his stay. On a standard scale for judging drug reactions, the authors rated kratom the probable cause of the liver inflammation (Naranjo score 6) and naltrexone doubtful (score 0), because the enzymes were raised before the injection.

He had taken oral and injected naltrexone before without problems. The authors suggest a test dose of oral naltrexone or injected naloxone before starting injectable naltrexone, partly because kratom may not show up on most routine urine drug screens.

Limits

• It describes one person, so it can't say how often this happens.
• The timing of his last kratom use came from his own report, which later urine tests contradicted.
• He left the program early, so his liver tests couldn't be followed after day 47.

What it means if you're considering naltrexone

Kratom acts on the same opioid receptors that naltrexone blocks, so a regular kratom user can go into withdrawal when naltrexone is started, even without other opioids. The authors stress asking about herbal supplements such as kratom before naltrexone is started.

The liver problem in this case was put down to kratom, not to naltrexone.