Tricyclic antidepressant plasma level monitoring: an improvement over the dose-response approach.

Monitoring plasma levels of tricyclic antidepressants (TCAs) can facilitate treatment response by providing objective guidelines for dosage adjustment. It provides a means of assessing the patient's compliance and ensuring the maintenance of an adequate medication trial while avoiding the complications of drug toxicity. The traditional dose-response method of medication adjustment depends on several assumptions that are not met in the case of TCAs, which makes plasma monitoring particularly useful for patients receiving most TCAs.