Which drug class requires at least two weeks in between starting or stopping another antidepressant drug class?

The correct answer is monoamine oxidase inhibitors (MAOIs) because this class of antidepressants has significant interactions with other antidepressant medications as well as with certain foods and beverages. MAOIs work by irreversibly inhibiting the enzyme monoamine oxidase, which is responsible for breaking down neurotransmitters such as serotonin, norepinephrine, and dopamine. This mechanism can lead to potentially dangerous interactions if an MAOI is used in conjunction with other classes of antidepressants, especially SSRIs and SNRIs, as it can increase the risk of serotonin syndrome—a serious and potentially life-threatening condition resulting from an excess of serotonin in the brain.

To mitigate these risks, it is recommended to allow a washout period of at least two weeks when switching from or to an MAOI. This ensures that the original drug is sufficiently cleared from the system, reducing the likelihood of adverse effects associated with the combination of antidepressants.

While other classes of antidepressants—such as SSRIs, SNRIs, and tricyclic antidepressants (TCAs)—can also have interactions, they do not generally require as prolonged a washout period when starting or stopping treatments compared to MAOIs. Therefore, understanding the unique pharmacological profile of MAO