Amitriptyline [Neurosurgery Wiki]

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====== Amitriptyline ======

Amitriptyline is a tricyclic antidepressant (TCA) with analgesic, sedative, and anticholinergic properties. It is widely used for both psychiatric and non-psychiatric conditions.

===== Classification =====
  * **Class:** Tricyclic antidepressant (TCA)
  * **ATC code:** N06AA09

===== Mechanism of Action =====
  * Inhibits reuptake of **serotonin (5-HT)** and **norepinephrine (NE)** in the central nervous system.
  * Blocks **muscarinic**, **histaminergic (H1)**, and **alpha-adrenergic** receptors, contributing to its side effects.

===== Indications =====
  * **Major depressive disorder**
  * **Neuropathic pain** (e.g., diabetic neuropathy, postherpetic neuralgia)
  * **Chronic tension-type headache** and **migraine prophylaxis**
  * **Fibromyalgia**
  * **Irritable bowel syndrome** (off-label)
  * **Tinnitus-related anxiety or depression** (off-label)

===== Dosage (Typical) =====
  * Starting: 10–25 mg at bedtime
  * Titration: Increase gradually based on response
  * Max: 150–300 mg/day (lower in elderly or for non-psychiatric uses)

===== Adverse Effects =====
  * **Common:** Dry mouth, constipation, urinary retention, sedation, weight gain, dizziness
  * **Serious:** Cardiac arrhythmias, QT prolongation, seizures, orthostatic hypotension
  * **Toxicity:** Narrow therapeutic index; risk of fatal overdose due to cardiac toxicity

===== Contraindications =====
  * Recent **myocardial infarction**
  * **Arrhythmias**
  * Concurrent **MAO inhibitor** therapy
  * **Angle-closure glaucoma**

===== Monitoring =====
  * ECG in patients >40 years or with cardiac history
  * Monitor for **anticholinergic toxicity**
  * Assess for suicidal ideation, especially early in treatment

===== Clinical Notes =====
  * Effective at **low doses** (10–50 mg) for pain and sleep-related symptoms
  * Sedative effect useful in patients with **insomnia**
  * Use with caution in **elderly** due to anticholinergic burden

===== Synonyms and Brand Names =====
  * **Brand names:** Elavil®, Tryptizol®, Saroten®
  * **Generic:** Amitriptyline hydrochloride