Untoward effects of lithium treatment in children aged four through six years.

Objective: To explore the relationship between lithium dose and serum lithium level on the occurrence of untoward or toxic effects of lithium in the treatment of 20 hospitalized aggressive and/or mood-disordered children aged 4 through 6 years.

Method: Clinical and research records of 20 children treated with lithium according to an established inpatient protocol were reviewed. Side effects as reported by psychiatric staff were categorized by organ system affected and severity.

Results: During the initial 2 weeks of lithium treatment, 60% of the children manifested one or more types of side effects, most commonly central nervous system effects. Side effects were seen at doses of 25.6 to 52.1 mg/kg per day and at serum levels from 0.65 to 1.37 mEq/L. In general, adverse effects were associated with higher lithium doses and lithium levels and were most common during the first week of treatment. A potential interaction between concurrent infection and more severe side effects was seen.

Conclusions: Side effects occur frequently in children aged 6 years and younger during the initiation phase of lithium treatment; are related to higher milligram per kilogram doses, higher serum lithium levels, and phase of treatment; and may be related to concurrent medical illness.