Prolactin stimulating effects of amoxapine and loxapine in psychiatric patients.

The effects of acute and chronic administration of a new antidepressant, amoxapine, on serum prolactin levels were compared to the effects of loxapine, its parent compound, which is a widely used neuroleptic. Serum prolactin levels were significantly elevated after amoxapine. These elevations were not significantly different from those of patients given loxapine. This suggests that amoxapine, in contrast to most other antidepressants, can block dopamine receptors at the anterior pituitary, which usually is associated with blockade of dopamine receptors in the striatum and limbic system, leading to extrapyramidal side effects and antipsychotic properties, respectively. The implications of these findings for the clinical use of amoxapine are discussed.