Study On The Factors In Plasma Lamotrigine Concentrations And Its Clinical Practice In Epileptic Children

Summary: We investigated the influence of age, dose, type of comedication on steady state plasma lamotrigine (LTG) concentrations on a total of 59 blood samples from 50 epileptic patients aged 3 to 28 years. The results showed the plasma concentration of LTG significantly increased with increasing the dosage or plasma valproic acid concentration and significantly decreased with increasing the age or carbamazepine concentration (P < 0.01). The 95% confidence interval estimated according to 30 LTGesponders was 2.49-4.5911 g/ml and apparently different from the lower limit of the recommended therapeutic range for the LTG concentration (1-411 g/ml) proposed by some investigators. The relationship between drug level and clinical response was also assessed in this population. Remarkable discrepancies were observed, indicating further studies on the potential value of monitoring plasma LTG concentrations. Clinical response was evaluated in 35 children aged ~ 14 years who received adjunctive LTG therapy (2mg/kgld) for intractable epilepsy, with 48.6% of cases showing a marked improvement in seizure frequency after 3 month treatment. The dosage was also assessed according to steady state plasma LTG concentrations in this population, confirming that children receiving concomitant enzyme-inducing antiepileptic drugs require a higher LTG dosage and those receiving valproic acid a lower dosage. Chinese children may be given lower dosage because of their different constitutions from the foreigners and plasma LTG concentrations should be monitored to optimise the dose.