MAO inhibitors for treatment-resistant depression: Bringing an updated perspective on pioneering drugs

In the 1950s, monoamine oxidase inhibitors transformed the pharmacological treatment of mental disorders as the first class of antidepressant drugs. Currently considered third-line medications for treatment-resistant depression, they are markedly underutilized. Despite the benefits of these drugs, controversies exist due to their potential for serious adverse effects. These now have well-recognized mechanisms of action, making them much less common and potentially preventable. It is important to study and teach the pharmacology of monoamine oxidase inhibitors again in order to revive their use in severely depressed patients, as well as in those who have experienced multiple treatment failures.