PHARM | TCAs Amitriptyline

💊 PHARM STUDY GUIDE: AMITRIPTYLINE (Elavil) Class: Tricyclic Antidepressant (TCA)🧠 MOA (80/20): Blocks neuronal reuptake of serotonin & norepinephrine; also anticholinergic, antihistamine, and sodium-channel effects → efficacy + side-effect burden. NCBI📋 Indications (what you’ll actually see):Major depressive disorder Off-label, low dose: neuropathic pain, migraine prevention, insomnia (sedating).⚠️ Red-Flag Side Effects (Prioritize 🚨):Cardiac toxicity – QT prolongation, conduction block, ventricular arrhythmias; overdose can be fatal. Monitor ECG/electrolytes in risk pts. Serotonin syndrome (with MAOIs/serotonergics): fever, agitation, hyperreflexia, diarrhea, tremor, clonus. Stop drug; supportive care; consider cyproheptadine.Anticholinergic crisis – delirium, urinary retention, ileus, hyperthermia (elderly esp.).Orthostatic hypotension & falls (α1-blockade).Suicidality boxed warning in children, adolescents, young adults—highest risk at start & dose changes. 🩺 Nursing Interventions & Monitoring:Baseline & periodic BP/HR, ECG if cardiac risk, electrolyte check (K/Mg) if QT risk. Screen for suicidal ideation early and with any dose change. Watch for anticholinergic effects (bowel regimen, fluids), falls, urinary retention.Assess for drug interactions (see below) and serotonin syndrome.🚫 Contraindications & Dangerous Combos:MAOIs: contraindicated; 14-day washout (risk of hyperpyrexia/convulsions/SS). Strong CYP2D6 inhibitors (e.g., fluoxetine, paroxetine) ↑ TCA levels → toxicity; avoid or adjust/monitor closely. Additive QT-prolonging meds (amiodarone, macrolides, antipsychotics) → arrhythmia risk. Potentiation with other anticholinergics/CNS depressants (falls, delirium). 🎯 Top 5 High-Yield Takeaways:Powerful but not first-line due to side effects/toxicity—reserve for refractory depression or low-dose pain/migraine.Cardiac safety first: screen QT risks, consider baseline ECG. Night dosing, slow titration, and taper to discontinue. Avoid MAOIs; beware CYP2D6 inhibitors (e.g., fluoxetine). Monitor suicidality, anticholinergic burden, falls, and serotonin syndrome. 🧩 80/20 Summary: Think TCA = reuptake block + anticholinergic + cardiac risk. Safe use = low & slow, night dose, ECG when needed, interaction check, taper, monitor mood & SS.