Amitriptyline

Amitriptyline

[10mg tablets 6 cents, 25mg tablets 3 cents]

ADMINISTRATION ROUTES:

  • PO, NG

ALTERNATIVE NAMES:

  • Amirol and Amitrip

ICU INDICATIONS:

  1. neurogenic pain (eg GBS)
  2. nocturnal sedation

PRESENTATION AND ADMINISTRATION:

  • PO / NG:
    Amirol 10mg (light blue), 25mg (yellow); Amitrip 10mg (blue), 25mg (yellow), 50mg (orange). Tablets may be crushed for nasogastric administration

DOSAGE:

  • Neurogenic pain and nocturnal sedation in the ICU:
    Commence at 10mg at night; increase to 25mg to 50mg as tolerated

    Note: the usual dose for treatment of depression is up to 75-300mg per day (this dose is rarely appropriate in ICU patients)

DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:

  • Dose as in normal renal function

DOSAGE IN PAEDIATRICS:

  • In view of the lack of experience with the use of this drug in paediatric patients, it is not recommended for patients under 12 years of age. Quoted paediatric dosing for enuresis is 1-1.5mg/kg at night.

CLINICAL PHARMACOLOGY:

  • Amitriptyline is an antidepressant with sedative effects. It is also used in treatment of neurogenic and chronic pain. Its mechanism of action is unclear.

CONTRAINDICATIONS:

  1. Hypersensitivity to amitriptyline
  2. Should not be given concomitantly with monoamine oxidase inhibitors.
  3. This drug is not recommended for use during the acute recovery phase following myocardial infarction.

WARNINGS

  • Amitriptyline should be used with caution in patients with a history of seizures and, because of its atropine-like action. Amitriptyline has been reported to produce arrhythmias, sinus tachycardia, and prolongation of the conduction time. Myocardial infarction and stroke have been reported with drugs of this class.

PRECAUTIONS

  • General:
    See WARNINGS
  • Laboratory Tests:
    No tests in addition to routine ICU tests are indicated
  • Drug/Laboratory Test Interactions:
    None known.

IMPORTANT DRUG INTERACTIONS FOR THE ICU

  • Increased sedation when combined with other sedative drugs.

ADVERSE REACTIONS

  • Body as a Whole:
    Hyperpyrexia; Lupus-like syndrome (migratory arthritis, positive ANA and rheumatoid factor).
  • Cardiovascular System:
    Myocardial infarction; stroke; nonspecific ECG changes and changes in AV conduction; heart block; arrhythmias; hypotension, particularly orthostatic hypotension; syncope; hypertension; tachycardia; palpitation.
  • Digestive System:
    Paralytic ileus; constipation; dry mouth; rarely hepatitis.
  • Nervous System:
    Seizures; hallucinations; ataxia; tremors; peripheral neuropathy; numbness, tingling, and paresthesias of the extremities; extrapyramidal symptoms; drowsiness.
  • Skin:
    Rash, itch

Critical Care Drug Manual

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