The British Medical Journal has featured a case report of the accumulation of baclofen in a patient with renal dysfunction.

The report describes a 61 year old woman with end stage renal disease who was receiving haemodialysis and was admitted with Staphylococcus epidermidis discitis; vancomycin and narcotic analgesics were started. She had a history of hypertension, diabetes, and calciphylaxis. In her fourth week in hospital, oral baclofen 5 mg three times daily was prescribed for back pain and muscle spasms.

Within 12 hours of starting the baclofen, the patient became disoriented, and by 36 hours had deteriorated to a Glasgow coma score of 8, and baclofen toxicity was diagnosed. The baclofen was therefore stopped and 12 hours after the last dose, she underwent a four hour haemodialysis treatment. Mental status improved, and after a second four hour treatment on the next day, she was her usual self.

The authors then describe the results of a literature search which identified a total of 18 reports of 33 people with baclofen toxicity in the context of low kidney function, and suggests that kidney function must be considered when prescribing baclofen.