Understanding antidepressant mechanism of action and its effect on efficacy and safety

Common side effects of antidepressants, such as weight gain, sexual dysfunction, and fatigue and sleepiness, may be attributable to their mechanisms of action. Antidepressants are neurotransmitter uptake blockers, enzyme inhibitors, and neurotransmitter receptor blockers. Various mechanisms of action can determine how quickly therapeutic benefit becomes apparent and whether certain acute and persistent side effects occur. Understanding mechanism of action can help clinicians select appropriate antidepressants for individual patients and manage adherence problems due to intolerability. Although more research is needed to further elucidate specific antidepressant mechanisms of action, clinicians can use current knowledge to tailor treatment decisions, such as switching patients to a medication with a different mechanism of action when intolerable adverse events are experienced.