Efficacy, safety and tolerability of Gabapentin as monotherapy for dystonic cerebral palsy

Objectives: To study the effectiveness of Gabapentin as monotherapy in dystonic cerebral palsy compared to accepted conventional therapy and understand its safety and tolerability.

Methods: A prospective, double-blind, randomised controlled trial was conducted in children with predominantly dystonic cerebral palsy. They were scaled for motor severity by Gross Motor Functional Classification system(GMFCS), quality of life by PedsQL Cerebral Palsy Module, dystonia by Barry-Albright Dystonia Scale(BADS) and Movement Disorder Childhood Rating Scale(MD-CRS) and randomised for treatment with gabapentin or trihexyphenidyl. The scales were administered on first visit, first followup(week 12) and second followup(week 24). Through physician interview at each visit, side effects were noted and doses adjusted.

Results: 37 children were enrolled, mean age 4.76 years, M:F ratio 1.78:1. Tolerated doses of gabapentin ranged 23.0-50 mg/kg/day, reduction needed in 10% due to side effects, tolerated trihexyphenidyl doses ranged 0.1-0.8 mg/kg/day, reduction needed in 37.5%. Each score displayed significant difference in percentage change at V1 and V2 as compared to baseline. Mean percentage change in scores from the baseline at V1 and V2 for gabapentin group and trihexyphenidyl group showed no significant difference among the two: p-value at V1 being BADS 0.19, MD-CRS 0.71, PedsQL 0.72 and p-value at V2 being BADS 0.22, MD-CRS 0.79, PedsQL 0.86. Incidence of side effect was comparable in both groups. Most common side effect with gabapentin- drowsiness, increased urinary frequency; with trihexyphenidyl- drowsiness, hypotonia.

Conclusion: This study gives evidence that Gabapentin is as efficacious as conventional drug therapy for dystonic cerebral palsy with good tolerability.
Keywords: Gabapentin, trihexiphenidyl, dystonic, cerebral palsy