Analgesic Effect of IV Acetaminophen in Tonsillectomies

Summary

Acetaminophen (paracetamol) is a first-line antipyretic and analgesic for mild and moderate pain for pediatric patients. Its common use (particularly in oral form) is underscored by its wide therapeutic window, safety profile, over the counter accessibility, lack of adverse systemic effects (as compared with NSAIDS and opioids) when given in appropriate doses. Although the exact anti-nociceptive mechanisms of acetaminophen continue to be elucidated, these mechanisms appear to be multi-factorial and include central inhibition of the cyclo-oxygenase (COX) enzyme leading to decreased production of prostaglandins from arachidonic acid, interference with serotonergic descending pain pathways, indirect activation of cannabinoid 1 (CB1) receptors and inhibition of nitric oxide pathways through N-methyl-D-aspartate (NMDA) or substance P. Of the above mechanisms, the most commonly known is that of central inhibition of COX enzymes by which the decreased production of prostaglandins diminish the release of excitatory transmitters of substance P and glutamate which are both involved in nociceptive transmission (Anderson, 2008; Smith, 2011). To date, several studies have shown acetaminophen's opioid sparing effect in the pediatric population when given by the rectal or intravenous routes (Korpela et al, 1999; Dashti et al, 2009; Hong et al, 2010).

Timeline

Start

2012-10

Primary completion

2015-11

Completion

2016-07

Publications

• Background Anderson BJ. Paracetamol (Acetaminophen): mechanisms of action. Paediatr Anaesth. 2008 Oct;18(10):915-21. doi: 10.1111/j.1460-9592.2008.02764.x.
• Background Smith HS. Perioperative intravenous acetaminophen and NSAIDs. Pain Med. 2011 Jun;12(6):961-81. doi: 10.1111/j.1526-4637.2011.01141.x. Epub 2011 May 31.
• Background Korpela R, Korvenoja P, Meretoja OA. Morphine-sparing effect of acetaminophen in pediatric day-case surgery. Anesthesiology. 1999 Aug;91(2):442-7. doi: 10.1097/00000542-199908000-00019.
• Background Dashti GA, Amini S, Zanguee E. The prophylactic effect of rectal acetaminophen on postoperative pain and opioid requirements after adenotonsillectomy in children. Middle East J Anaesthesiol. 2009 Jun;20(2):245-9.
• Background Hong JY, Kim WO, Koo BN, Cho JS, Suk EH, Kil HK. Fentanyl-sparing effect of acetaminophen as a mixture of fentanyl in intravenous parent-/nurse-controlled analgesia after pediatric ureteroneocystostomy. Anesthesiology. 2010 Sep;113(3):672-7. doi: 10.1097/ALN.0b013e3181e2c34b.

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Indications