Indeed, in much of the world, tricyclics are still commonly considered to be first-line antidepressants for general use. However, due to safety issues, we have them as a first line option only in the more severe forms of major depression delineated in this algorithm. It is worth noting that the USA Food and Drug Administration has become very focused on the risks brought about by drugs with conduction, particularly QTc problems. They are not approving or restricting new drugs that have even mild problems in this area. They are starting to require revisions of the package inserts of older drugs, too, having just added strong warnings about thioridazine.
Tricyclics have similar concerns.
They too are at higher risk of the cardiac side effects. These at the least add inconvenience factors compared to using the other agents that we list as first line. For patients with severe melancholic depression, if you follow the algorithm there, we DO have tricylics as first line. We also have them first line as the antidepressant of choice to combine with an antipsychotic for psychotic depression. We have the tricyclics as last choice, pretty much, for bipolar depression because of the evidence that they promote rapid cycling more than the others.