Which antidepressant mechanism is most associated with hypertensive crisis when tyramine-rich foods are ingested?
- A Selective serotonin reuptake inhibition (SSRI)
- B Irreversible inhibition of monoamine oxidase A and B (non-selective MAO-I) ✓
- C Tricyclic antidepressant norepinephrine-serotonin reuptake blockade
- D Reversible inhibition of MAO-A (RIMA) at therapeutic doses
Correct answer: B. Irreversible inhibition of monoamine oxidase A and B (non-selective MAO-I)
Explanation
Non-selective irreversible MAO inhibitors (e.g., phenelzine, tranylcypromine) block both MAO-A and MAO-B in the gut and liver. Normally, intestinal MAO-A metabolizes dietary tyramine; with MAO-I, absorbed tyramine triggers massive catecholamine release from sympathetic neurons, precipitating hypertensive crisis ('cheese reaction'). Reversible MAO-A inhibitors (moclobemide) are displaced by tyramine and pose less risk; TCAs and SSRIs do not inhibit MAO.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
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