Lamotrigine: pharmacokinetics

The pharmacokinetics of lamotrigine have been studied in single and multiple dose studies in animals, normal volunteers, and patients with epilepsy. Lamotrigine exhibits first-order linear pharmacokinetics. Lamotrigine is well absorbed with bioavailability approaching 100%. The absorption is unaffected by food and there is no first-pass metabolism. The volume of distribution is between 1.25 and 1.47 L/kg and protein binding is about 55%. The half-life of lamotrigine is between 24.1 and 35 hours in drug naive adults but may be altered by enzyme inducing and inhibiting drugs. Clinical trials demonstrated no evidence of autoinduction or saturable metabolism. Younger children (0.17 to 5 years) eliminate lamotrigine faster than older children (5 to 10 years). Children may be more prone to enzyme induction than adults.