Selective serotonin reuptake inhibitors Drugs related to tricyclic antidepressants are a mixed bag

Abstract

EDITOR, - N Freemantle and colleagues propose that, compared with selective serotonin reuptake inhibitors, “newer tricyclic and related antidepresants … will have similar impact on rates of suicide but at considerably less cost.”1 The drugs that are listed as newer tricyclic and related antidepressants, however, have important differences in pharmacology, clinical profile, toxicity, and cost. Maprotiline is indeed related to tricyclic antidepressants both structurally and pharmacologically. It is also equally toxic,2 as table 1 of the authors' article clearly shows. To class it among compounds that are of “similar toxicity” to selective serotonin reuptake inhibitors is misleading and a serious error. Trazodone and mianserin are relatively safe in overdose but differ from selective serotonin reuptake inhibitors in being highly sedating.2 For some patients a sedating drug will be preferred,3 but this will be a clinical decision rather than an economic one. Economic factors may, of course, favour the use of one “safe” sedating antidepressant over another. Trazodone is as expensive as selective serotonin reuptake inhibitors, and, although mianserin is cheaper, the expense and inconvenience of the blood count monitoring required by the British National Formulary have not been taken into account in the costs shown by the authors. Viloxazine is used little in Britain. It was released on to the market before licensing authorities required new antidepressant drugs to undergo rigorous placebo controlled testing of efficacy. Its efficacy compared with that of placebo has not been satisfactorily shown,4 and calls for its more widespread prescription require careful examination. Lofepramine is non-sedating and relatively safe in overdose. It is indeed a viable alternative to the selective serotonin reuptake inhibitors in the treatment of major depression.3 Evidence suggests that it is more effective than placebo,5 but not at the dose that Freemantle and colleagues used …