The determination of amoxapine in human fatal overdoses

Amoxapine, a recently introduced dibenzoxazepine, has been found effective in clinical studies for the treatment of various types of depression. Two amoxapine related deaths, a 53-year-old white male and a 21-year-old white female, have been investigated by this office. Both had been prescribed amoxapine for depression. Quantitation of amoxapine was by gas chromatography using a 3% OV-17 column with confirmation by ultraviolet spectrophotometry and thin layer chromatography. Blood amoxapine concentrations were found to be 18 mg/L in the first subject, and 6.7 mg/L in the second subject. These concentrations are many-fold higher than the therapeutic serum concentrations of up to 0.21 mg/L reported in a clinical study. These cases illustrate the potential lethality of amoxapine overdosage and the need for caution in prescribing amoxapine to patients with suicidal tendencies.