The dual-action hypothesis: does pharmacology matter?
With treatment to remission as the gold standard for depression treatment, there is considerable reassessment of treatment approaches with the view to finding and employing agents capable of rapidly eliminating all symptoms and returning patients to normalcy. The mechanisms of action intrinsic to different classes of antidepressants are at the center of this review. The selective serotonin reuptake inhibitors (SSRIs), the most commonly prescribed antidepressants, have a single-action mechanism involved in modulating the reuptake of the neurotransmitter serotonin. The selectivity of the SSRIs renders them safer and more tolerable than the earlier multi-acting monoamine oxidase inhibitors (MAOIs) and the tricyclic antidepressants (TCAs). However, because serotonin is not the only neurotransmitter implicated in the pathophysiology of depression, the selectivity that bestows safety to SSRIs may limit somewhat the antidepressant effect in some patients. A newer class of dual-action antidepressants acts by inhibiting the reuptake of both serotonin and norepinephrine. These serotonin-norepinephrine reuptake inhibitors (SNRIs) have improved side effect profiles compared with the earlier multi-action antidepressants, compare favorably with the SSRIs on safety and tolerability, and reduce depression and its associated symptoms with greater rapidity. This review compares the neurobiology of single- and dual-action mechanisms.
Shelton
Richard C
RC
Department of Psychiatry, Vanderbilt University School of Medicine, 1500 21st Ave., South, Suite 2200, Nashville, TN 37212, USA. Richard.Shelton@vanderbilt.edu
D018759:Adrenergic Uptake Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D000928:Antidepressive Agents / Q000494:pharmacology* / Q000627:therapeutic use*; D003865:Major Depressive Disorder / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D009638:Norepinephrine / Q000502:physiology; D011941:Receptors, Adrenergic / Q000187:drug effects; D011985:Receptors, Serotonin / Q000187:drug effects; D012701:Serotonin / Q000502:physiology; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D016896:Treatment Outcome
D018759:Adrenergic Uptake Inhibitors; D000928:Antidepressive Agents; D009638:Norepinephrine; D011941:Receptors, Adrenergic; D011985:Receptors, Serotonin; D012701:Serotonin; D017367:Selective Serotonin Reuptake Inhibitors