Doxepin up-to-date: a review of its pharmacological properties and therapeutic efficacy with particular reference to depression

Abstract

Doxepin is closely related in structure and general pharmacological properties to other tricyclic antidepressant drugs such as amitriptyline and imipramine. It combines antidepressant activity with a sedative effect and in this respect resembles amitriptyline, with which it shares a similar profile of clinical action. The mood elevating effect of doxepin appears to be similar to that of amitriptyline but is probably less marked than that of imipramine and in some studies has been slower to take effect than imipramine. At dosages which have achieved a similar overall response rate, doxepin tends to cause fewer or less troublesome side-effects than imipramine, amitriptyline or amitriptyline-prephenazine. The more marked sedative properties of doxepin make it more useful than imipramine in depressed patients with sleep distrubances and in depression associated with anxiety. The benzodiazepines remain the drugs of choice in anxiety states. but when anxiety is accompained by significant depression, doxepin is more effective than chlordiazepoxide or diazepam. Doxepin is usually well tolerated, and in particular by the elderly and those with cardiovascular disease. Side-effects are similar in nature to those of other tricyclic antidepressants, with dry mouth, drowsiness and constipation being the most common. Postural hypotension is uncommon. Although doxepin appears to cause fewer cardiovascular side-effects in usual therapeutic doses, it has an intrinsic cardiotoxicity on overdosage similar to other tricyclics.