Amitriptyline

PHARMACOLOGY

Tricyclic antidepressant that blocks the pre-synaptic uptake of serotonin and norepinephrine

Onset of action: analgesic effect after 3-7 days; up to 30 days for depression
Time to peak plasma concentration: 4 h PO
Plasma ½ life: 9-25 h PO

DOSING

  • Starting dose 10-25 mg HS PO titrating upward as required to 150 mg (higher doses rarely required in palliative care)
child.png
  • 500 mcg/kg HS PO

UNWANTED EFFECTS

  • Sedation
  • Dry mouth
  • Delirium
  • Postural hypotension
  • Fatigue
  • Hyponatremia
  • Headache
  • Urinary retention

PITFALLS/CONCERNS

  • Low doses should be used initially in the elderly
  • Sedation may affect performance of some tasks
  • Avoid abrupt withdrawal after discontinuation
  • Should not be used with an MAOI, recent myocardial infarction, arrythmias, mania or severe hepatic impairment

NOTE

This information is drawn from a number of sources (see below). The reader is encouraged to access these and other relevant literature for more detail. As always, sound clinical judgment should be used in individual clinical cases. In particular, it should be remembered that there may be significant variation in the pharmokinetics of a drug resulting from a number of factors, including the individual patient’s metabolism/disease status and how the medication has been formulated.

SOURCES/REFERENCES

  1. Brunton LL, Lazo JS, Parker KL, editors. Goodman and Gilman’s: the pharmacological basis of therapeutics. 11th ed. McGraw-Hill Professional; 2006.
  2. Twycross R, Wilcock A. Palliative care formulary. 3rd ed. Radcliffe Medical Press Ltd; 2008.
  3. Repchinsky C, editor. Compendium of pharmaceuticals and specialties (CPS): the Canadian drug reference for health professionals. 44th ed. Canadian Pharmacists Association; 2009.
  4. Goldman A, Hain R, Liben S. Oxford textbook of palliative care for children. 1st ed. Oxford University Press; 2006.

Back to Pain

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License