Child and adolescent nortriptyline single dose kinetics predict steady state plasma levels and suggested dose: preliminary data.

The use of nortriptyline single dose kinetics to predict steady state plasma levels and suggested dose was investigated in 33 pediatric subjects who were diagnosed as having major depressive disorder. The data were analyzed separately for the 11 subjects 5 to 9 years old who received a single dose of 25 mg and a fixed daily dose of 20 mg of nortriptyline, and for the 22 subjects 10 to 16 years old who received a single dose of 50 mg and a fixed daily dose of 50 mg of nortriptyline (N = 17) or a fixed daily dose of 20 mg (N = 5) because of a very slow rate of metabolism of the drug. Correlations within the group of 5 to 9 years olds between the steady state plasma levels and the five sampling points after the single dose were all highly significant. Correlations between the steady state plasma levels within the group of 10 to 16 year olds and the five sampling points after the single dose and a fixed daily dose of 50 mg (N = 17) were also highly significant. Similar correlations for the total group of 10 to 16 year olds (N = 22) were performed (prorating the steady state plasma levels of the slow metabolizers), and these too were highly significant. Suggested dose schedules for each age group were developed from the regression equations of nortriptyline steady state plasma levels versus 24-hour nortriptyline plasma levels after the single dose. The regression equation for the group of 5 to 9 year olds was highly significant.(ABSTRACT TRUNCATED AT 250 WORDS)