Comparison of Lithium Dosage Methods for Preschool-and Early School-Age Children

Lithium may be useful in the treatment of prepubertal children with bipolar disorder or aggressive conduct disorder. However, there are few dosage guidelines. This study compares two dosage methods reported for prescribing lithium to prepubertal children: (1) a weight-based dosing schedule and (2) a single-dose, kinetics-based method. Lithium doses were calculated using each method and then compared with doses actually used in the clinical care of hospitalized children. No statistically significant differences were found between mean lithium dose estimates calculated by the two methods. Average lithium dose estimates for both kinetic and weight-based methods were less than the observed discharge doses. Differences were seen between the two methods for children weighing between 25 and 30 kg. The weight-based dosing schedule and the single-dose, kinetics-based methods for calculating lithium dose result in similar dosage estimates when applied to young children.