Nursing Field Notes / Psych-Mental Health Pharmacology · Antidepressant Ladder — Rung 4 of 3 (last line)
MAOI ☠️
Monoamine Oxidase Inhibitor — the powerful, last-resort antidepressant
NG-154PSYCH PHARMADHD-friendly visual edition
Very powerful antidepressants used for depression, panic disorder & social phobia — especially depression that is resistant to other meds. They sit at the top of the antidepressant ladder: last-line, because two things make them uniquely dangerous — tyramine food restrictions and a strict 2-week washout around other serotonergic drugs.
⏱️ 2-week washoutRequired before/after any other serotonergic antidepressant — no exceptions.
🚨 Serotonin syndromeAgitation, hyperthermia, clonus/hyperreflexia, diaphoresis, tremor — the shared danger when the washout rule is broken.
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WHAT IT DOES
STEP 1 · THE MECHANISM
One enzyme, shut down completely — three neurotransmitters flood the brain instead of just one.
🔬 Block the enzyme that breaks neurotransmitters down
MOA Monoamine oxidase (MAO) is the enzyme that normally breaks down norepinephrine, serotonin, and dopamine once they've done their job. MAOIs irreversibly block that enzyme — instead of blocking reabsorption like an SSRI, they stop the neurotransmitters from being destroyed at all, so all three build up in the brain.
🧠 "MAOI blocks the trash collector." No breakdown crew for NE, serotonin, or dopamine — everything piles up. That's why it's the most powerful class, and also why the interactions are the most dangerous.
💊 Know the names
Phenelzine — brand: Nardil
Selegiline
Isocarboxazid
Tranylcypromine
🧠 "MAOI's names don't rhyme like SSRIs do" — learn these four as a standalone set, since none of them share the familiar -ine/-am suffixes.
🎯 Indications
😔 Depression — especially treatment-resistant
😱 Panic disorder
😳 Social phobia
🧠 Powerful, but last resort — tried after SSRIs, SNRIs, and TCAs haven't worked.
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WATCH FOR
STEP 2 · THE TWO BIG DANGERS
This whole drug class is tested on two rules — food, and timing. Miss either one and the outcome is a crisis.
MAO normally breaks down tyramine too. With the enzyme blocked, dietary tyramine builds up, displaces stored norepinephrine, and triggers a massive release of norepinephrine → hypertensive crisis.
🧀Aged cheeseno wine tasting
🍷Wine
🍺Beerno beer fest
🥓Cured meatssausage, salami
🍫Chocolate
🧂OTC cold/diet medsdecongestants
🧠 "No wine tasting, no beer fest." Aged cheese & wine, beer & sausage/salami, chocolate — anything aged, fermented, cured, or tap. This is the single highest-yield MAOI fact on NCLEX.
⏱️ Danger #2 — the 2-week washout period
Never combine an MAOI with another serotonergic antidepressant — SSRIs, SNRIs, or TCAs — without a 2-week washout before starting the MAOI and after stopping it (fluoxetine needs even longer due to its long half-life, per most references).
🧠 "MAOI = Anti-depressant, STOP — count to 2 (weeks)." This washout rule appears on the SSRI page and the SNRI/TCA page too — it's the single rule that connects all four antidepressant classes.
🚨 Serotonin syndrome — same 5 signs as every other antidepressant class
If the washout rule is broken, or an MAOI is combined with another serotonergic drug, serotonin syndrome can occur:
🧠 "A HOT DAT" — Agitation · HOT (hyperthermia) · Diaphoresis · Agitation-driven Tremor + clonus. Also watch for headache and increased agitation as early warning NCLEX key terms when starting or increasing an MAOI dose.
📈 Suicide risk — assess first
Like all antidepressants, if a patient states "this med isn't working after 2 weeks," assess first for further expressions of hopelessness, despair, suicidal thoughts, or self-harm before addressing onset timing.
🧠 Increased suicide risk is a shared antidepressant-class concern, not unique to MAOIs — but it's still a top MAOI safety priority.
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TEACH
STEP 3 · PATIENT EDUCATION
Two rules to teach on day one — the diet list, and the drug-switching timeline.
💊 Check every OTC drug before taking it — including cold remedies & diet aids
3
⏱️ Never start or stop another antidepressant without a 2-week washout
4
💬 Report severe headache, palpitations, or stiff neck — possible early hypertensive crisis
🧠 "Cheese, wine, and two weeks." If a nursing exam question mentions MAOI, the answer usually involves one of those three things.
🪜 Where MAOIs sit on the antidepressant ladder
🥋 This page = the top rung · see NG-205 (SSRI) and NG-187 (SNRI/TCA)
🧪 NCLEX key terms to flag
Headache + increased agitation when starting or increasing dose
Massive HTN crisis risk = the word "tyramine" nearby
2-week washout = the phrase "switching antidepressants"
🧠 See NG-205 (SSRI) and NG-187 (SNRI vs. TCA) — all three antidepressant pages share the same serotonin syndrome symptom list and the same washout rule.
Q1: Why do MAOIs require a tyramine-restricted diet?
MAO normally breaks down dietary tyramine too. With it blocked, tyramine displaces stored norepinephrine, causing a massive NE release and hypertensive crisis.
Q2: Name three tyramine-rich foods/drinks to avoid.
Aged cheese, wine, beer, cured/fermented meats (sausage, salami), and chocolate.
Q3: A patient wants to switch from an SSRI to an MAOI. What must happen first?
A 2-week washout period, to prevent serotonin syndrome.
Q4: Where do MAOIs sit on the antidepressant treatment ladder, and why?
Last line — they're very powerful (increase NE, serotonin, AND dopamine) but carry the highest risk from food and drug interactions.