Pitfalls in measuring antidepressant drugs

Abstract

Depressions being a major problem, antidepressants are one of the most frequently used drugs in the clinical practice. Antidepressants are commonly measured in the laboratory for the purpose of therapeutic drug monitoring. Widely used antidepressants include tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs). Owing to narrow therapeutic range and higher toxicity, TCAs are a common cause of morbidity and mortality. In emergency situations, the assays of TCAs on urgent basis are needed. Although a number of assays are available for TCA, immunoassays are suitable for screening purpose in case of a suspected overdose. However, immunoassays for TCA also suffer from many limitations including cross-reactivity of active metabolites and are not suitable for therapeutic drug monitoring. Limitations of various assays for estimation of antidepressants and some tips to deal with these limitations are described. © 2008 Humana Press Inc.