The effect of age on plasma level of setiptiline maleate in depressed patients

1. Setiptiline maleate (SPT) was administered orally to 45 subjects aged 22-86 years and steady state plasma levels were determined by mass fragment chromatography (GC-MF) to examine the effect of aging on those values. 2. There was a significant correlation between the plasma levels and daily dose. However, there was a wide interindividual variability. 3. Dose-corrected plasma level (DC-PL), or values corrected by dividing the plasma level by daily dose/body weight, was used as the systemic drug clearance parameter. 4. DC-PL was compared among 7 age groups of the subjects distributed in 10-year-intervals. DC-PL showed no difference among groups of subjects between the > 29 years bracket to the 70 years bracket, but showed significantly higher values in those in the > 80 bracket compared to all age groups and subjects in the < 79 bracket. 5. There was a significant correlation between the age of patients and DC-PL according to polynomial response curve analysis. Regression analysis yielded the equation y = -52.72 + 7.05 x -0.17 x2 + 0.01 x3 (n = 45, r = 0.49, p < 0.01).