Stage One

The case at the door

Read it once. Watch for the clue. Tap to see the move.

Patient

A 38-year-old man with treatment-refractory depression is brought to the ED 45 minutes after dinner. He ate a charcuterie board (aged cheddar, salami, soppressata) and shared a bottle of red wine. He now has a sudden splitting occipital headache, palpitations, sweating, and flushing.

Vitals: BP 224/132, HR 118, RR 22, T 37.4 C. Pupils dilated. He is anxious and nauseated. His outpatient medication list includes phenelzine.

What is happening, and what do you reach for?

Tyramine-induced hypertensive crisis

Phenelzine is a non-selective irreversible MAOI. With MAO disabled in his gut and liver, the tyramine in aged cheese, cured meat, and red wine bypassed first-pass metabolism, flooded sympathetic nerve terminals, and displaced a tidal wave of norepinephrine. The result is a sudden hypertensive emergency.

First move: IV phentolamine, a non-selective alpha blocker. It directly reverses the alpha-1 vasoconstriction driving the BP. Nitroprusside is the backup. A beta-blocker by itself would be a mistake here.

Stage Two

Four clues, one diagnosis

When any three of these line up in a stem, the answer is tyramine crisis. Stop hunting.

MAOI on board

Phenelzine, tranylcypromine, or isocarboxazid. Refractory depression or atypical depression history.

Trigger meal < 1 hour

Aged cheese, cured meat, red wine, draft beer, soy sauce, or fermented foods within an hour of onset.

Sudden BP spike

Systolic often above 200. Onset over minutes, not hours. Often paired with bradycardia from baroreceptor reflex.

Adrenergic surge symptoms

Occipital thunderclap headache, palpitations, drenching sweats, flushing, nausea, photophobia.

Stage Three

Watch the mechanism flip

Same meal. Same gut. The only variable is whether monoamine oxidase is still working. Toggle to see what changes.

MAO degrades tyramine first-pass. NE stays parked. BP is boring.

Tyramine from food

Norepinephrine stored in vesicles

MAO in gut and liver (the gatekeeper)

NET uptake channel on the nerve terminal

Stage Four

The forbidden plate

High-tyramine foods. Tap each one to see why it lands on the no-list. The unifying theme is aging, curing, or fermentation: any bacterial decarboxylation of tyrosine cranks up tyramine content.

Aged cheese

cheddar, blue, brie

Cheese reaction

The original named trigger. Long aging means more bacterial tyrosine decarboxylation. Fresh mozzarella and cottage cheese are safer.

Cured meat

salami, soppressata, pepperoni

Aged protein

Bacterial breakdown of tyrosine during curing piles up tyramine. Fresh meat cooked the day it was bought is fine.

Soy sauce

tamari, fish sauce

Fermented condiment

Fermented soy is loaded. Sushi night with phenelzine is a trip to the ED.

Miso

soy paste, tempeh

Fermented soy

Same bacterial decarboxylation problem as soy sauce. Miso soup is not a free pass on an MAOI.

Red wine

chianti especially

Aged ferment

Chianti is the named offender. Tyramine content depends on aging and bacterial activity during fermentation.

Draft beer

tap beer, not bottled

Unpasteurized

Draft and unpasteurized beer keep live yeast working. Bottled pasteurized beer is much safer in small amounts.

Sauerkraut

kimchi, pickled cabbage

Lacto-fermented

Lactobacillus fermentation produces tyramine. Same logic for kimchi.

Fava beans

broad beans

L-dopa load

Fava beans carry levodopa and tyramine. Double trouble on an MAOI: extra catecholamine substrate plus the displacement engine.

Selegiline at low dose (10 mg/day or less) is MAO-B selective and does not strip the gut of MAO-A, so the dietary restriction is far looser. At higher doses selegiline loses selectivity and the diet rule comes back.

Stage Five

Treatment ladder

Goal is to drop BP fast without overshooting and without creating unopposed alpha vasoconstriction. Pick the rung that matches the physiology.

1

Phentolamine IV

Non-selective alpha blocker

The problem is alpha-1 vasoconstriction from a flood of NE. The fix is to directly block alpha-1. Phentolamine is short-acting and titratable. First-line and what the board wants.

2

Nitroprusside IV

Arterial and venous vasodilator (NO donor)

Acceptable if phentolamine is unavailable or if BP is refractory. Acts downstream of the receptor by relaxing vessel smooth muscle. Watch for cyanide toxicity on prolonged infusion and follow thiocyanate levels.

X

Beta-blocker monotherapy

Plain propranolol or metoprolol alone

Avoid. Beta-blockade without alpha-blockade leaves alpha-1 vasoconstriction unopposed; BP gets worse, not better. Same trap as pheochromocytoma. If you must use a beta blocker, only after alpha is already blocked, or use mixed alpha-beta blockade (labetalol) with caution.

Stage Six

The other MAOI trap

Tyramine crisis is not the only way to crash on these drugs. Serotonin syndrome is the other half of the MAOI safety story.

Serotonin syndrome alert

MAOI + serotonergic = ICU

An MAOI plus any of the agents below stacks serotonin to dangerous levels. Watch for the triad: autonomic instability (HTN, tachycardia, hyperthermia), neuromuscular hyperactivity (clonus, hyperreflexia, rigidity), and altered mental status.

SSRIfluoxetine, sertraline

SNRIvenlafaxine, duloxetine

Triptanssumatriptan

Opioidmeperidine, tramadol

Antibioticlinezolid

OTCdextromethorphan, St. John's wort

Two-week washout rule. Stop the MAOI for at least 14 days before starting any serotonergic drug, and the same when going the other direction. Fluoxetine needs 5 weeks because of its long half-life metabolite. Skip the washout and you can land a patient in the ICU.

Stage Seven

Choose before reveal

Do the bedside split first: tyramine crisis, serotonin syndrome, or allergic reaction.

A patient on phenelzine develops headache and diaphoresis 40 minutes after aged cheese. BP is 224/126, lungs are clear, skin has no urticaria, and neurologic exam shows no clonus. What lane is this?

Meal within an hour plus MAOI plus severe hypertension points to tyramine crisis. No urticaria or hypotension means not anaphylaxis. No clonus or hyperthermia means not serotonin syndrome.

Same patient, BP 230/132. Which pressure drug matches the receptor problem?

Alpha-1 vasoconstriction is the problem. Phentolamine blocks alpha receptors. Beta blocker alone can leave alpha-1 unopposed.

Visual check

Food triggers to recognize

These are pattern anchors, not diagnostic photos. Tap to enlarge.

Stage Eight

Lock it in

Five original vignettes. Read all five choices first, then hunt the stem for the clue.

0/5

Study maps

Tyramine Crisis

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