What is a serious side effect of MAOIs?

Monoamine oxidase inhibitors (MAOIs) are a class of antidepressants that can lead to a serious side effect known as a tyramine-induced hypertensive crisis. This occurs when patients consume foods that are high in tyramine—such as aged cheeses, fermented products, and cured meats—while taking MAOIs. MAOIs inhibit the enzyme monoamine oxidase, which normally breaks down tyramine in the body. If tyramine levels rise significantly due to this inhibition, it can lead to a rapid increase in blood pressure, potentially resulting in a hypertensive crisis, which is a medical emergency characterized by severe headaches, nausea, and other symptoms.

While dry mouth, sleep disturbances, and increased appetite can occur as side effects of MAOIs, they are not considered serious or life-threatening like a hypertensive crisis. The risk associated with tyramine ingestion is significant enough that patients are given strict dietary restrictions to avoid such a crisis while on MAOIs, highlighting the importance of understanding this potential risk.