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Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities
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Published on: July 29, 2014

Age- and therapy-related effects on morphine requirements and plasma concentrations of morphine and its metabolites

N J Bouwmeester1, J N van den Anker, W C J Hop

  • 1Department of Anaesthesiology, Erasmus MC/Sophia, Dr Molewaterplein 60, NL-3015 GJ Rotterdam, the Netherlands. j.bouwmeester.1@erasmusmc.nl

British Journal of Anaesthesia
|April 17, 2003
PubMed

Insights

Neonates require different morphine dosing than older children due to altered metabolism. Age is the key factor influencing morphine needs and plasma levels in pediatric patients post-surgery.

Area of Science:

  • Pharmacology
  • Pediatric Anesthesiology
  • Clinical Pharmacology

Background:

  • Investigating clinical variables influencing morphine requirements and plasma concentrations in pediatric patients.
  • Focus on gestational age, sex, weight, therapeutic regimens, and mechanical ventilation.
  • Understanding factors affecting morphine pharmacokinetics and pharmacodynamics in neonates and infants.

Purpose of the Study:

  • To determine the impact of age on morphine requirements and plasma concentrations in pediatric surgical patients.
  • To compare continuous versus intermittent morphine administration for postoperative pain management.
  • To analyze morphine and its metabolites (M3G, M6G) in different pediatric age groups.

Main Methods:

  • Double-blind study involving neonates and infants stratified into four age groups.
  • Morphine administration: initial bolus followed by continuous infusion or intermittent boluses.
  • Pain assessment using COMFORT and visual analogue scales; plasma concentrations of morphine and metabolites measured over 24 hours.

Main Results:

  • Age was the most significant factor affecting morphine requirements and plasma concentrations.
  • Neonates required significantly less additional morphine and had higher plasma concentrations of morphine and its metabolites.
  • No significant difference in morphine requirements between continuous and intermittent administration methods.

Conclusions:

  • Neonates possess a narrower therapeutic window for postoperative morphine analgesia compared to older children.
  • Intermittent and continuous morphine administration showed similar safety and effectiveness across age groups.
  • Optimal morphine infusion rates and plasma concentrations for infants over one month were established.
Abstract

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