March 18, 2011 by dailybolusoflr
Akathisia is defined as both:
· an objective component of observable restlessness
· a subjective component of inner restlessness
The side effect of akathisia is known to be related to medications such as neuroleptics (typically after long term use) as well as in the acute setting in patients receiving drugs such as haloperidol, prochlorperazine and metoclopramide.
(It has been and still is an underestimated side effect. Many patients simply don’t know why they suddenly feel like they need to leave the ED or feel like they are freaking out. I have had a couple patients who simply disappeared from the ED in the midst of their migraine treatment who I suspect had unrecognized akathisia.)
Research has focused on:
· the incidence of akathisia related to metoclopramide
· its relationship to the rapidity of administration
· whether or not its development can be decreased with the co-administration of diphenhydramine. (Note: that in patients who develop akathisia, diphenhydramine is the treatment of this side effect).
Points to Know:
· The faster you give metoclopramide, the more likely your patient will develop akathisia. FDA approved administration is bolus over 2 minutes or infusion over 15 minute. You should always choose the 15 minute infusion, as this will help decrease the incidence.
· Some people use higher doses of metoclopramide (20mg) for the treatment of chemo-related nausea or in the treatment of migraines.
o The higher the dose of metoclopramide, the higher the incidence of akathisia.
o Literature is split on whether or not prophylactic diphenhydramine decreases the incidence of akathisia in these patients or if it simply decreases the subjective component for the patient (i.e. how restless they feel vs. how restless they look).
o Most authors agree, for higher doses (i.e. 20mg) there is some benefit to 25mg IV diphenhydramine
o There is no clear benefit for the standard 10mg dose
Regan Am J Emerg Med. 2009 May;27(4):475-80.
Linda Regan, MD FACEP
Program Director, Emergency Medicine Residency
Johns Hopkins Medical Institutions