Patients with kidney dysfunction who were prescribed a high dose of a common muscle relaxant - Baclofen, had increased chances of being admitted to a hospital, a new study has found.

These patients were more likely to end up in a hospital for disorientation and confusion than those who weren't prescribed the drug, according to the study published in the journal JAMA and were also presented at the American Society of Nephrology meeting in Washington D.C. "When we looked at people with low kidney function (30 per cent or less) who received a high dose of baclofen from their prescriber, approximately one in 25 were being admitted to hospital with severe confusion, typically over the next few days," said Dr Amit Garg, Professor at Western's Schulich School of Medicine & Dentistry and Scientist at ICES and Lawson.

"If you compare that to a group of people who had low kidney function who didn't get baclofen, that risk is less than one in 500, so it's quite a dramatic difference between the two groups," Dr Garg added. Study co-author Dr Peter Blake, Professor at Schulich Medicine & Dentistry, Lawson scientist said that this drug is commonly prescribed for muscle spasms and muscle pain, and is also prescribed off-label for alcoholism, gastro-esophageal reflex disease, and trigeminal neuralgia. He says it is widely prescribed because it has not previously been associated with serious side-effects.

"It came to my clinical attention dealing with patients with advanced kidney failure, that this drug that is generally thought to be relatively harmless, appeared to be the precipitant of severe confusion," said Dr Blake. "These are patients who had previously been very oriented, and they were suddenly extremely confused and when you took a history, we understood that they had recently started this drug, baclofen," the co-author explained. Using ICES data, researchers looked at a group of approximately 16,000 people in Ontario with kidney disease who started a new dose of baclofen between 2007 and 2018.

They divided the patients into two groups - one that received a high dose, and second, that received a low dose of the drug and compared both to a group of almost 300,000 kidney disease patients who weren't prescribed the drug at all. The team found that 1.11 per cent of such patients (108/9707) who started a high dose of the drug baclofen were admitted to hospital with cognitive-related symptoms, versus 0.42 per cent (26/6235) with the low dose. They found that the group most at risk had the lowest kidney function, 3.78 per cent of patients with kidney function less than 30 per cent were hospitalized with these symptoms after starting a high dose of baclofen (26/687).

"We found that the risk for hospitalisation for severe confusion was higher amongst patients who received doses that were higher versus doses that were lower," Dr Garg said.