A 66-year-old male was prescribed phenelzine (Nardil) while in an acute psychiatric unit for recalcitrant depression. The nurse practitioner (NP) managing his primary health care needs to understand the following regarding phenelzine and other monoamine oxidase inhibitors (MAOIs):

Phenelzine (Nardil) is a monoamine oxidase inhibitor (MAOI) used in treatment-resistant depression. MAOIs increase levels of serotonin, norepinephrine, and dopamine by inhibiting their breakdown, which significantly improves mood in refractory cases. However, this mechanism also creates a high risk for serious drug and food interactions, including hypertensive crisis and serotonin syndrome. Safe use requires strict dietary restrictions and careful medication review across all healthcare settings. Rationale: A. Patients taking Phenelzine (Nardil) must avoid other serotonergic medications such as SSRIs, SNRIs, tramadol, and certain migraine medications due to the risk of serotonin syndrome. Excess serotonin accumulation can lead to agitation, hyperthermia, autonomic instability, and potentially life-threatening complications. A mandatory washout period is required when switching between serotonergic agents and MAOIs. B. MAOIs require strict dietary restrictions because foods high in tyramine, such as aged cheeses, cured meats, fermented products, and certain alcoholic beverages, can trigger dangerous hypertensive crises. Phenelzine (Nardil) inhibits tyramine metabolism, leading to excessive norepinephrine release and severe vasoconstriction. Patient education about diet is a critical safety component of therapy. C. MAOIs have extensive drug interactions with many commonly prescribed medications, including sympathomimetics, decongestants, certain analgesics, and other antidepressants. These interactions can result in hypertensive crisis or serotonin toxicity. Patients on Phenelzine (Nardil) require thorough medication reconciliation before any new prescriptions are given across all healthcare settings. D. All options are correct because MAOIs such as Phenelzine (Nardil) require avoidance of serotonergic drugs, strict dietary tyramine restriction, and careful evaluation of all potential drug interactions. These combined precautions are essential to prevent life-threatening complications and ensure safe long-term management of treatment-resistant depression.