Antidepressant challenge tests: the interface of pharmacokinetics and pharmacodynamics

Antidepressant compounds have been used as probes in neuroendocrine challenge tests designed to assess the functional responsivity of central neurotransmitter systems. Neurohormonal responses to the antidepressants desipramine and clomipramine, for example, can provide information regarding noradrenergic and serotonergic function, respectively. Pharmacokinetic factors can affect these antidepressant challenge tests. Proper attention to pharmacokinetic issues in the design, implementation, and analysis of data obtained with these probes will provide a more clear understanding of the pharmacodynamic meaning of the results from studies that apply antidepressant challenges.