For individuals with pre-existing kidney problems, high doses of the muscle relaxant baclofen may increase the risk of a serious brain disease, known as encephalopathy, according to the findings of a recent study.
In findings published last month in the Journal of the American Medical Association (JAMA), Canadian researchers indicate that side effects of baclofen may be linked to a significantly increased the risk of encephalopathy in patients with chronic kidney disease, at doses of 20 mg per day or greater.
Baclofen is a muscle relaxant first introduced in 1992, and originally sold under the brand name Gablofen. It is now widely available in generic form, and is also sold under the brand name Lioresal in Canada.
In this latest report, researchers conducted a retrospective population-based cohort study in Ontario from 2007 to 2018, involving nearly 16,000 adults ages 66 or older with chronic kidney disease. They looked at exposures greater or equal to 20 mg per day or less than 20 mg per day, and compared them with reports of encephalopathy, which can manifest as delirium, disorientation, dementia, stroke, and changes to awareness.
According to the findings, 61% of patients were prescribed doses of 20 mg per day or more, and 39% were prescribed amounts of less than 20 mg per day. Of those given the higher doses, 1.11% suffered encephalopathy within the first 30 days. By comparison, only 0.42% of those given the lower doses had an encephalopathy diagnosis.
However, compared to non-users, both high and low baclofen doses resulted in increased risks. Those given higher doses were nearly 20 times more likely to suffer encephalopathy compared to nonusers. Those given lower doses were also still nearly six times as likely to suffer brain disease than those not taking the drug.
“Among older patients with CKD who were newly prescribed baclofen, the 30-day incidence of encephalopathy was increased among those prescribed higher doses compared with lower doses,” the researchers concluded. “If verified, these risks should be balanced against the benefits of baclofen use.”