Nortriptyline pharmacokinetics and plasma levels: implications for clinical practice.

The pharmacokinetics of TCAs are reviewed with particular emphasis on nortriptyline, the agent most extensively studied. The clinical uses of TCA plasma level-response studies are discussed in relationship to rational dosage adjustment to increase response rates and avoid iatrogenic toxicity. Other important topics discussed include the issue of active metabolites, single-dose prediction studies, and special considerations in treating the elderly and the medically ill.