Amoxapine (Asendin, Lederle Laboratories)

Amoxapine is a tricyclic antidepressant agent, which is chemically related to the antipsychotic agent loxapine, but which appears to block selectively the neuronal reuptake of norepinephrine; it is qualitatively similar to desipramine. In studies of patients with mixed depressive illnesses, amoxapine is at least as effective as amitriptyline and imipramine and probably more effective than placebo in ameliorating depressive symptoms. Claims of more rapid onset of therapeutic effects are based on group mean data obtained from small samples of depressed patients with heterogeneous and imprecisely defined diagnostic types. Amoxapine has yet to be compared with desipramine or maprotiline, the most pharmacologically similar antidepressants. Biopharmaceutical and pharmacokinetic data are limited, and a relationship between serum concentrations and efficacy has not yet been shown. Acute toxicity and drug interaction documentation are also lacking. At this time, amoxapine represents a chemical alternative to traditional tricyclic antidepressants. There are no consistent data indicating superiority of amoxapine over any other antidepressant agent for any specific symptom constellation, in rate or extent of improvement, or in any particular diagnostic or demographic population. Studies in which amoxapine is compared with pharmacologically similar agents at therapeutically equivalent doses in diagnostically homogeneous groups are needed to establish the drug's true place in the treatment of depressions.