Gabapentin (Neurontin (R)) is a gamma-aminobutyric acid analogue indicated
in adults for adjunctive treatment of partial seizures with or without seco
ndary generalization. Two studies were conducted to determine the single-do
se pharmacokinetics of gabapentin in healthy subjects age 1 month to 12 yea
rs and to guide dose selection in safety and efficacy trials in pediatric p
atients. Forty-eight subjects were given single oral doses of gabapentin (1
0 mg/kg) while fasting. Enrollment was homogeneously distributed throughout
the age range. Plasma samples were drawn predose and then serially for 24
hours postdose. Single doses of gabapentin were well tolerated by healthy p
ediatric subjects. Plots of pharmacokinetic parameters versus age suggested
significant differences between younger (1 month to < 5 years) and older (
greater than or equal to5 to 12 years) subjects. Mean area under the plasma
concentration-time curve from zero to infinity (AUC((0-infinity))) was 25.
6 mug(.)h/ml in younger subjects and 36.0 mug(.)h/ml in older subjects (p <
0.001). Corresponding mean peak plasma concentrations (C-max) were 3.74 an
d 4.52 mug/ml (p < 0.05). Oral clearance (normalized for body weight) was 7
.40 and 4.41 ml/min/kg in younger subjects and older subjects, respectively
(p < 0.001). It was concluded that children between 1 month and < 5 years
of age require approximately 30% higher daily doses of gabapentin than thos
e greater than or equal to 5 to 12 years of age.