Mastering Medical
USMLE Step 1 · Pharmacology

SSRIs and SNRIs vs TCAs, MAOIs, and atypical antidepressants

How to tell SSRIs and SNRIs and TCAs, MAOIs, and atypical antidepressants apart when a board question makes them look alike.

Fastest separator

SSRI/SNRI questions center on reuptake and tolerability; TCA/MAOI questions center on toxicity and interactions.

Side by side

SSRIs and SNRIsTCAs, MAOIs, and atypical antidepressants
Key clue

SSRI sexual dysfunction/GI effects or SNRI blood pressure effect from serotonin and norepinephrine reuptake blockade.

TCA anticholinergic/cardiotoxic overdose, MAOI tyramine crisis, or atypical patterns such as bupropion seizure risk and mirtazapine weight gain.

Mechanism

Newer reuptake inhibitors increase serotonin with or without norepinephrine while avoiding much receptor promiscuity.

Older or atypical antidepressants add receptor blockade, monoamine breakdown inhibition, or dopamine/norepinephrine effects.

Labs and tests

Sertraline sexual dysfunction points SSRI; venlafaxine hypertension points SNRI.

Amitriptyline wide QRS points TCA; phenelzine with aged cheese hypertension points MAOI.

The trap

All treat depression, but overdose pattern and food/drug interaction clues separate the classes.

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The repair move

For antidepressants, attach the adverse-effect signature before choosing the class.

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Core

A patient with depression starts sertraline and later develops sexual dysfunction and GI upset. Which antidepressant class is most likely?

Show answer and explanation

Answer: A. SSRI. SSRIs selectively increase serotonin signaling and commonly cause sexual dysfunction and GI symptoms.

Why the other choices are tempting

  • B. SNRIs increase serotonin and norepinephrine and may raise blood pressure.
  • C. TCAs have anticholinergic, antihistamine, alpha-blocking, and cardiotoxic overdose effects.
  • D. MAOIs have major food and drug interaction risks including hypertensive crisis.
  • E. Bupropion is more dopaminergic/noradrenergic and is less associated with sexual dysfunction.

Flashcards

Tap a card to flip it.

What is the fastest separator for SSRIs and SNRIs vs TCAs, MAOIs, and atypical antidepressants?

SSRI/SNRI questions center on reuptake and tolerability; TCA/MAOI questions center on toxicity and interactions.

What clue should make you choose SSRIs and SNRIs?

SSRI sexual dysfunction/GI effects or SNRI blood pressure effect from serotonin and norepinephrine reuptake blockade.

Quick answers

What is the fastest way to tell SSRIs and SNRIs from TCAs, MAOIs, and atypical antidepressants?

SSRI/SNRI questions center on reuptake and tolerability; TCA/MAOI questions center on toxicity and interactions.

What is the key clue for SSRIs and SNRIs?

SSRI sexual dysfunction/GI effects or SNRI blood pressure effect from serotonin and norepinephrine reuptake blockade.

What is the key clue for TCAs, MAOIs, and atypical antidepressants?

TCA anticholinergic/cardiotoxic overdose, MAOI tyramine crisis, or atypical patterns such as bupropion seizure risk and mirtazapine weight gain.

What is the common trap with SSRIs and SNRIs vs TCAs, MAOIs, and atypical antidepressants?

All treat depression, but overdose pattern and food/drug interaction clues separate the classes.