PHARMACOKINETICS OF GAMMAHYDROXYBUTYRATE (GHB) IN NARCOLEPTIC PATIENTS

Sodium gammahydroxybutyrate (GHB) is an endogenous compound that has b een under investigation in the management of narcolepsy for about two decades. The data confirm that GHB treatment decreases daytime sleepin ess and episodes of cataplexy, sleep paralysis, and hypnagogic halluci nations. The current study evaluated the pharmacokinetics of GHB, give n twice in one night to six narcoleptic patients who had been chronica lly taking GHB nightly on a similar basis. Results confirmed earlier r eports and showed nonlinear pharmacokinetics. Maximum concentrations w ere reached in 40+/-6.2 and 35.7+/-7 minutes after the first and secon d dose respectively. Mean AUC(inf) was 17731.6+/-4867 mg/mL/m. Mean GH B T-1/2 was 53+/-19 minutes. GHB elimination appears to be capacity-li mited in some patients when administered at a fixed dose of 3 g twice nightly at a 4-hour interval.