Pharmacology · Serotonin Pharmacology
SSRIs, MAOIs, washout rules, and atypical antidepressants
Abbreviations: SSRI = selective serotonin reuptake inhibitor · SNRI = serotonin-norepinephrine reuptake inhibitor · MAOI = monoamine oxidase inhibitor · SERT = serotonin transporter · SIADH = syndrome of inappropriate antidiuretic hormone · CYP = cytochrome P450 · QT = corrected QT interval
| Agent | Distinguishing Feature | Key Interaction | Clinical Note |
|---|---|---|---|
| Fluoxetine | Longest half-life; active metabolite norfluoxetine | CYP2D6 inhibitor; 5-week washout before MAOI | Least discontinuation syndrome risk |
| Sertraline | Fewest drug interactions | Minimal | Preferred in pregnancy and elderly |
| Paroxetine | Shortest half-life; most anticholinergic | CYP2D6 inhibitor | Highest discontinuation syndrome risk |
| Escitalopram | Fewest drug interactions of class | QT prolongation at high doses | S-enantiomer of citalopram |
Sexual dysfunction (most common discontinuation reason) · Gastrointestinal upset (early) · Insomnia · SIADH/hyponatremia (elderly) · Black box: suicidality under age 25
MAOI + SSRI/SNRI → Serotonin syndrome (potentially fatal)
MAOI + meperidine → Serotonin syndrome (use morphine instead)
MAOI + tyramine-rich foods → Hypertensive crisis
Suggested References
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