The tricyclics are an older class of antidepressants; most depressed patients now receive SSRIs or Wellbutrin, largely because these drugs have fewer side-effects. Nonetheless, doctors often give tricyclics to patients who do not respond to SSRIs (an occasional problem in elderly patients); a few of them are given when a sedative effect is desired. Although nobody entirely understands why these drugs alleviate depression, researchers do know that the tricyclics block the reuptake of norepinephrine and serotonin (the sedating antidepressants affect acetylcholine too).
Tricyclics, their generic names, and their sedative effects:
Brand Name......Generic Name.........Sedative Effect
Adapin..........doxepin..............high
Anafranil.......clomipramine.........low
Aventil.........nortriptyline........moderate
Elavil..........amitriptyline........high
Norpramin.......desipramine..........low
Pamelor.........nortriptyline........moderate
Sinequan........doxepin..............high
Surmontil.......trimipramine.........high
Tofranil........imipramine...........moderate
Vivactil........protriptyline........low
culled from various sources, including A Primer of Drug Action, Robert Julien