Toxicity of newer versus older antidepressants

Of all the controversies over the different medi cations used in psychiatry, there is probably least dispute about the effectiveness of antidepressants in controlling depressive illness. However, the choice of which antidepressant to use is bedevilled by the spectre of potential toxicity from adverse effects, interactions and overdose. The unwanted effects may vary from mild and tolerable to potentially lethal. At one time it was relatively easy to become familiar with the problems surrounding the original two main groups of antidepressants the tricyclic antidepressants (TCAs) and the monoamine oxidase inhibitors (MAOIs). Recent years have seen the introduction of a number of newer drugs, with a wide range of chemical structures and differing pharmacological activities. They also have a new spectrum of adverse effects and interactions. It is worth reviewing the major differences between old and new antidepressants, and to identify the areas in which clinical caution must be exercised in order to avoid pitfalls and maximise clinical benefit.