Which type of interaction is associated with MAOI and SSRI leading to a dangerous condition?

• A. Serotonin syndrome
• B. Hypertensive crisis
• C. Neuroleptic malignant syndrome
• D. Anticholinergic delirium

Answer: (A)

Combining an MAOI with an SSRI creates a pharmacodynamic interaction that dramatically raises serotonin levels in the brain. MAOIs prevent the breakdown of serotonin, while SSRIs prevent its reuptake, so using them together can push serotonin activity into a toxic range. This leads to serotonin syndrome, a dangerous condition whose features include mental status changes (like agitation or confusion), autonomic instability (such as high blood pressure and fever), and neuromuscular symptoms (like tremor, rigidity, and hyperreflexia or clonus). Hypertensive crisis can occur with MAOI reactions in other contexts (often involving tyramine-containing foods or other pressors), but the classic dangerous interaction with an SSRI is serotonin syndrome. Neuroleptic malignant syndrome stems from dopamine blockade, and anticholinergic delirium comes from antimuscarinic effects, not from this serotonergic drug combination.