Opioid equipotency conversions for hospitalized infants: a systematic review

Abstract

Hospitalized infants commonly receive opioids to reduce pain and minimize distress during invasive procedures. However, infant neurodevelopment is significantly impacted by cumulative and prolonged opioid exposures. While opioid conversion has been studied extensively in adults, no standardized equipotency opioid conversions exist for hospitalized infants and opioid stewardship efforts are inconsistent. We performed a systematic review to identify opioid dosing conversions commonly used in hospitalized infants <1 year of age, finding fourteen articles which documented or cited a calculation of cumulative opioid exposure. Morphine milligram equivalents (MME) conversion factors varied widely, with nine studies citing conversion equivalent equations commonly used in adults. Efforts to expand safe opioid stewardship to hospitalized infants will require evidence-based consensus for opioid equipotency dose conversions which acknowledge the unique physiology of infants.

Fig. 1. PRISMA flow diagram.

Study flow of literature search and exclusions.

Fig. 2. Opioid doses equianalgesic to morphine milligram equivalents (MME).

Opioid doses equianalgesic to MME for intravenous fentanyl, hydromorphine, oral oxycodone, and oral methadone. 1 – source populations from which each paper’s cited conversion factors were derived. 2 – Gil et al. [38] did not document equianalgesic dose in text, instead referencing Patanwala [46] who documented fentanyl equianalgesic dose as a range from 0.01 to 0.02mg IV fentanyl equivalent to 1 IV MME. 3 – Resnick et al. [44] did not document equianalgesic dose in text, instead referencing Gammaitoni et al. [47] who documented oxycodone equianalgesic dose as a range from 2 to 3mg oral oxycodone equivalent to 1 IV MME.