Sodium oxybate for cataplexy

OBJECTIVE: To review the pharmacology, pharmacokinetics, clinical efficacy, adverse effects, drug interactions, precautions, dosing recommendations, and patient counseling of sodium oxybate for the treatment of cataplexy in patients with narcolepsy. DATA SOURCES: OVID and PubMed databases were searched (1966-January 2006) using the key words sodium oxybate, gamma-hydroxybutyrate, narcolepsy, and cataplexy. Only English-language articles were selected. STUDY SELECTION AND DATA EXTRACTION: All information on sodium oxybate related to narcolepsy and cataplexy was considered. Study selection included human trials evaluating safety and efficacy of sodium oxybate for the treatment of cataplexy. DATA SYNTHESIS: Sodium oxybate is approved by the Food and Drug Administration for the treatment of excessive daytime sleepiness and cataplexy in patients with narcolepsy. In placebo-controlled trials, sodium oxybate demonstrated efficacy in reducing the number of cataplexy attacks. The dosing regimen includes a split dose given at bedtime and 2.5-4 hours later due to its short elimination half-life. The drug is generally well tolerated, with headache, nausea, dizziness, pain, and somnolence being the most common adverse events. CONCLUSIONS: Sodium oxybate is safe and effective for the treatment of cataplexy. Potential disadvantages include a multiple dosing regimen, abuse potential, cost, and a closed distribution system. Potential advantages demonstrated in clinical trials include significant decreases in the number of weekly cataplexy attacks, improvement in daytime sleepiness, and improvement in the Clinical Global Impression of Change score and nighttime awakenings. Overall, sodium oxybate provides a new option for the treatment of cataplexy.