Sodium oxybate in the treatment of childhood narcolepsy-cataplexy: a retrospective study

To evaluate the efficacy and side effect profile of sodium oxybate in the treatment for narcolepsy-cataplexy in the pediatric age group.

A retrospective study was conducted on 15 children and adolescents with narcolepsy-cataplexy who had been treated with sodium oxybate. The mean age at diagnosis of narcolepsy was 11 years (range 3-17 years). Subjects were followed for 3-90 months (mean 33) after starting sodium oxybate. During this period of time they were also maintained on other medications for sleepiness (n=14) and cataplexy (n=6). The charts were reviewed for documentation of improvement in sleepiness or cataplexy, side effects, and functioning in daily life.

Subsequent to the addition of sodium oxybate, sleepiness improved in 13/15 patients. In patients who had Epworth Sleepiness Scale (ESS) assessments, the score fell from a baseline median of 18 to 12 (n=10, p=0.01). The number of cataplexy episodes estimated by parents decreased from a median of 38/week pre-treatment to <1/week post treatment (n=14, p<0.001). Cataplexy severity, measured on an arbitrary scale, fell from a median of 3 (severe) to 1 (mild) in all 15 subjects (p<0.001). Two of the 15 patients (13%) discontinued sodium oxybate, one for insurance reasons and the other due to constipation and dissociative feelings. A third patient stopped the medication temporarily due to body aches and dizziness, but then resumed treatment without recurrence of symptoms. Side effects in four others included tremor, blurring of vision, nocturnal awakenings, and increased nightmares. Overall, side effects occurred in 6/15 (40%) individuals. Improvement in social/academic spheres was noted in 11/15 (73%) subjects after starting sodium oxybate. The median BMI before and after treatment remained unchanged at 23 (n=14, p=0.99). Median values of height and weight before and after treatment also did not change significantly. The mean dose of sodium oxybate was 5 ± 2 g. Dose escalation owing to development of tolerance was not encountered.

Sodium oxybate is effective in alleviating sleepiness and cataplexy in childhood onset narcolepsy-cataplexy. The therapeutic response was sustained over time, and without development of tolerance. Forty percent of the subjects experienced adverse effects.