Sampling Time, Dosage Schedule, and Nortriptyline Plasma Levels

Therapeutic Drug Monitoring of Nortriptyline in Smoking Cessation: A Multistudy Analysis

“…Ethnic differences in the metabolism of tricyclic antidepressants have been observed in Asians as well as in Africans and African Americans 19 , 20 . Data specific to nortriptyline are few but are concordant with our findings 21 , 22 . Kishimoto and Hollister 22 found that, after a single 100 mg dose of nortriptyline in 20 men (Japanese, N =10; American, N =10 (race not specified)), Japanese participants achieved numerically superior maximum plasma concentrations (39.3 vs 32.0 ng/ml) and significantly higher exposure, as assessed by area under the curve (AUC) (1150 vs 730 ng/h/ml).…”

“…Evidence of slower metabolism or clearance for another tricyclic antidepressant, desipramine, has been seen in Chinese or mixed Asian samples compared to Caucasians [28,29]. Ziegler et al, (1977) observed that nortriptyline concentrations were nearly 50% higher in African-Americans than Whites (113.5 vs.75.7 ng/mL). The potential genetic basis for ethnic differences in PNCs likely relates to differences in the frequency of defective CPY2D6 alleles (i.e., so-called "poor metabolizers"), with a higher rate of defective alleles for this enzyme generally, but not always, observed in Asians and those of African ancestry [30][31][32][33][34][35].…”

“…Evidence of slower metabolism or clearance for another tricyclic antidepressant, desipramine, has been seen in Chinese or mixed Asian samples compared with Caucasian samples 23 , 24 . Ziegler et al 21 . observed that nortriptyline concentrations were nearly 50% higher in African Americans than white samples (113.5 vs 75.7 ng/ml).…”

Pharmacokinetic Aspects on Once-Daily Nortriptyline Administration

“…Thus, Ziegler et al (1976Ziegler et al ( , 1977 have performed two studies with a single bedtime dose and plasma level assays 12-16 or 11-20 h after dosage. In the former study steady state levels of 39-352 ng/ml were re corded in 18 patients on a mean dose of 127 mg.…”

Amitriptyline Blood Levels and Relapse

“…He confirmed that the once a day dosage schedule was effective, and found that although the variation in plasma nortriptyline concentration at the. four sampling times was small compared to interpatient variation, it appeared desirable to standardize the time of sampling to minimize variation (27). Our study did lack this element of standardization, but out-patients can seldom fit their personal lives around a standard time to draw blood.…”