Repeated ketamine infusions for arthritis pain: a 38-patient chart review

The question

Can repeated single-day intravenous ketamine infusions reduce long-term pain in people with chronic arthritis pain, and does their opioid use change?

What they did

Researchers looked back at the medical records of 38 consecutive patients treated at one outpatient private practice between January 2019 and December 2024. All had chronic pain from rheumatoid arthritis, osteoarthritis or psoriatic arthritis. Each received intravenous ketamine (300-500 mg per session, about 1-1.5 mg/kg/h over a 3-hour session) under conscious sedation with vital-sign monitoring, repeated roughly every 3 to 12 months (median 6 months). People with advanced cardiovascular disease, sleep apnea or a history of substance misuse were not offered infusions.

What they found

The group was 35 women and 3 men, aged 21 to 73 (median 58), with a median body mass index of 33 and an average of 3 sources of chronic pain. Median pain scores fell from 8 at baseline to 4 at 3 months and remained at 4 at 24 months. Nineteen patients reported more than 50% pain relief at 3 months and 20 did at 24 months, while 8 patients got minimal or no benefit. The number of patients taking opioids fell from 18 to 10 at 24 months, and the median morphine milligram equivalent among those still taking them went from 45 to 30.

The fine print

This was a retrospective chart review at a single private clinic with only 38 patients, no comparison or placebo group, and no blinding, so natural changes in arthritis pain, other treatments or expectation effects could explain part of the results. Pain scores were self-reported, the group was mostly women, and people with certain health conditions were excluded, so results may not apply broadly. The abstract does not report side effects or how many patients were lost to follow-up. This summary is based on the abstract only.

What it means

In one clinic’s records, repeated ketamine infusions were followed by lower reported pain and less opioid use over two years in most, but not all, arthritis patients; without a control group, this cannot show that ketamine caused the improvement.

Evidence grade: Low. A small retrospective review of clinic records with no control group, no blinding and no randomization, so improvement cannot be separated from other causes.

This summary is based on the study’s published abstract.