Which antidepressant mechanism is responsible for the 'cheese effect' (hypertensive crisis) seen when certain foods are consumed?

• A MAO-A inhibition preventing metabolism of ingested tyramine in the gut wall and liver ✓
• B Reuptake inhibition of serotonin leading to excess synaptic 5-HT
• C Blockade of alpha-2 autoreceptors releasing noradrenaline
• D Inhibition of dopamine reuptake causing peripheral vasopressor activity

Explanation

Tyramine, found in aged cheeses, red wine, and pickled foods, is normally inactivated by MAO-A in the intestinal wall and liver (first-pass metabolism). Non-selective MAOIs (phenelzine, tranylcypromine) block this inactivation, allowing tyramine to reach systemic circulation where it releases stored noradrenaline from sympathetic terminals, causing severe hypertension. This is the classic 'tyramine pressor response' or cheese effect.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.