Estimated equipotent conversion ratios of morphine, sufentanil and fentanyl as continuous infusion in neonatal intensive care units: a pharmacoepidemiologic cohort study.

PURPOSE

Opioids are frequently used to treat pain in neonatal intensive care units (NICU) with fentanyl, morphine and sufentanil being mainly used agents. Equianalgesic potency between opioids is not clearly described in the neonatal population. The aim of this study was to compare theoretical and actual equipotent conversion ratios between morphine, sufentanil and fentanyl based on prescriptions.

METHODS

In this observational, multicentric, pharmacoepidemiologic study, prescriptions' data (doses, duration of use, patients' characteristics) were collected and analyzed for all neonates hospitalized in one of the 30 Level III French NICUs using the same prescription software (Logipren®) and who received at least one prescription of morphine, sufentanil or fentanyl as continuous infusion during a 6-year period (2014-2020).

RESULTS

Among 65,555 neonates, 8361 (12.8%) received a prescription of continuous opioid infusion in one of the 30 French NICUs: 5054 (60.4%) received sufentanil, 2413 (28.9%) morphine and 894 (10.7%) fentanyl. After conversion to equipotent morphine doses using theoretical conversions ratios of 50:1 for morphine/fentanyl ratio and 500:1 for morphine/sufentanil ratio, prescribed mean maintenance doses of fentanyl and sufentanil were two times and five times higher than morphine doses, respectively. In this cohort, potency conversion ratios between the different opioids were 20:1 for morphine/fentanyl ratio and 100:1 for morphine/sufentanil ratio, and 4:1 for fentanyl/sufentanil ratio (theoretical conversion ratio of 7: 1).

CONCLUSION

In a large cohort of neonates treated with continuous opioids in NICU, fentanyl and sufentanil doses used were significantly higher than morphine doses when using theoretical conversion ratios.