Preliminary data on the relationship between nortriptyline plasma level and response in depressed children.

Twenty-two subjects 6-12 years old who met Research Diagnostic Criteria and DSM-III criteria for major depressive disorder received a fixed daily dose of nortriptyline during an 8-week protocol. Weekly plasma levels were measured; the raters performing behavioral assessments were blind to these levels. There was a highly significant difference between the mean steady-state plasma levels and the milligram-per-kilogram doses of the responders and nonresponders. The data suggest that the lower limit of the therapeutic range of nortriptyline in children (over 60 ng/ml) is similar to that reported for adults. The disadvantages of the use of a milligram-per-kilogram dose rather than a pharmacokinetic approach are discussed.