Prevalence and risk factors of baclofen neurotoxicity in patients with severely impaired renal function

The most common adverse effect of baclofen, used for managing hiccups and spasticity, is neurotoxicity. As baclofen is primarily excreted by the kidneys, neurotoxicity is more likely to occur in patients with chronic kidney disease (CKD). We evaluated the risk factor for baclofen neurotoxicity and the recommended dosage for patients with severe CKD.

In this single-center retrospective study, we classified 401 patients with CKD as stage 4 (n=174), non-dialysis stage 5 (n=97), and on-dialysis (n=130).

The prevalence of baclofen-induced neurotoxicity in patients with severe CKD was 7.0% (28 of 401 patients). There was no significant difference in the presence of neurotoxicity when the patients were classified as CKD stage 4, stage 5, and dialysis patients. There were significant differences in serum albumin levels and the presence of diabetic nephropathy between the patients with neurotoxicity and those without. The results from a multiple logistic regression analysis showed that serum albumin was independently associated with baclofen neurotoxicity (p=0.007). The minimum daily dose for baclofen neurotoxicity was 10mg, 10mg, and 5mg in patients with CKD stages 4 and 5, and dialysis, respectively.

In this study, the prevalence of baclofen-induced neurotoxicity in patients with severe CKD was 7.0%. Serum albumin was identified as an independent risk factor for neurotoxicity. We recommend initially administering a daily dose of 7.5mg for patients with severe CKD stages 4 and 5, and a daily dose of 2.5mg for patients receiving dialysis.