Amoxapine is an antidepressant of the dibenzoxazepine class, chemically distinct from the dibenzazepines, dibenzocycloheptenes, and dibenzoxepines.
It is designated chemically as 2-Chloro-11-(1-piperazinyl)dibenz[b,f][1,4]oxazepine. The structural formula is represented below:
C17H16CIN3O M.W. 313.78
Amoxapine is supplied for oral administration as 25 mg, 50 mg, 100 mg and 150 mg tablets.
Amoxapine Tablets USP, 25 mg, 50 mg, 100 mg and 150 mg contain: dibasic calcium phosphate, magnesium stearate, starch (corn), and stearic acid.
Amoxapine Tablets USP, 50 mg and 150 mg also contain: FD&C Yellow No. 6.
Amoxapine Tablets USP, 100 mg also contain: FD&C Blue No. 2.
Amoxapine is an antidepressant with a mild sedative component to its action. The mechanism of its clinical action in man is not well understood. In animals, amoxapine reduced the uptake of norepinephrine and serotonin and blocked the response of dopamine receptors to dopamine. Amoxapine is not a monoamine oxidase inhibitor.
Amoxapine is absorbed rapidly and reaches peak blood levels approximately 90 minutes after ingestion. It is almost completely metabolized. The main route of excretion is the kidney. In vitro tests show that amoxapine binding to human serum is approximately 90%.
In man, amoxapine serum concentration declines with a half-life of eight hours. However, the major metabolite, 8-hydroxyamoxapine, has a biologic half-life of 30 hours. Metabolites are excreted in the urine in conjugated form as glucuronides.
Clinical studies have demonstrated that amoxapine has a more rapid onset of action than either amitriptyline or imipramine. The initial clinical effect may occur within four to seven days and occurs within two weeks in over 80% of responders.