First-dose pharmacokinetics of lithium carbonate in children and adolescents

Bipolar I disorder (BP-I) in children and adolescents is associated with substantive psychosocial dysfunction and human suffering [1, 2]. Safe and effective treatments are needed to reduce symptomatology and improve quality of life for the vulnerable youngsters and families impacted by this illness. Lithium is a benchmark treatment for adults suffering from bipolar illness [3], with evidence of benefit dating back almost 60 years [4]. However, there has been relatively little research regarding the use of lithium in the treatment of youths suffering from mania [5]. Given this paucity of information, a Written Request (WR) was issued by the Food and Drug Administration (FDA) under the auspices of the Best Pharmaceuticals for Children Act (BPCA) (FDA 2002) for the study of this agent in youths. In response, a contract was awarded to rigorously study lithium in children and adolescents with mania. A key step in developing evidence-based dosing paradigms for any compound is the characterization of the drug s pharmacokinetics (PK) [6]. Therefore, two of the goals of this contract were to characterize the pharmacokinetics of lithium and to develop evidence-based dosing for lithium in children and adolescents [7]. Although many studies have examined the PK of lithium in adults [8a??10], relatively little is known about the PK of lithium in pediatric patients. Vitiello et al. [11] described lithium PK in nine children (aged 9a??12 years) with a DSM-III-R primary diagnosis of conduct disorder or adjustment disorder. Subjects received one single 300 mg dose of lithium carbonate. The disposition of lithium in these children appeared to generally be similar to that seen in adults. However, their elimination half-life and greater total lithium clearance were shorter than reported in adult studies. The present study was performed in order to describe the first dose PK of lithium in children and adolescents. In addition to characterizing the disposition of lithium in children and adolescents with BP-I, we also explored whether patient-specific characteristics (e.g. age, gender and weight) influence the PK of lithium in this patient population.