Amoxapine versus amitriptyline for continuation therapy of depression

The efficacy of continuation therapy with tricyclic antidepressants has been established in a number of controlled trials. This study investigated the efficacy of continuation therapy with a relatively new antidepressant, amoxapine, using a double-blind controlled comparison with amitriptyline. Subjects met DSM-III criteria for major depressive disorder and were randomized to treatment with either amoxapine 400 mg (N = 47) or amitriptyline 300 mg (N = 45). The acute phase lasted up to 8 weeks. Responders were continued on the same drug at the same dose for a 16-week continuation phase. Some measures found more rapid onset for amitriptyline, which is inconsistent with findings from some prior studies. Amitriptyline was more effective in inducing full recovery. There was a trend for higher relapse rates on amoxapine, perhaps related to the fact that there were more partial responders entering continuation therapy from this group. Side effect rates were equivalent in the two drugs. However, physicians rated amoxapine's side effects as more frequently interfering with its therapeutic effect. These data suggest that amoxapine does not offer any clear advantage over amitriptyline for continuation therapy in patients who have major depressive disorder. Of potential clinical relevance is the finding that achieving full recovery in the acute phase may reduce the likelihood of relapse in the continuation phase, regardless of the type of antidepressant medication prescribed.