What must be considered in coadministration of morphine and fentanyl?
Fentanyl is 100 times as potent as morphine, thus co-administration at the maximum doses in the ALS PCS, would be double the recommended opioid dose, causing significant respiratory, cardiovascular and CNS depression risk to the patient. It is, therefore, not recommended. Rather, it is recommended to use multimodal analgesia where possible; i.e. the co-administration of opioids, NSAIDs and acetaminophen.
There are occasions when it may be beneficial to switch between opioids, e.g. from fentanyl to morphine when on a long offload delay, however this requires a patch to the BHP. The purpose of the patch, at RPPEO, is for the paramedic and physician to consult on the positive and negative effects the opioid has had on the patient, and to proceed cautiously with the addition of another opioid. Since analgesia has already been administered and any urgent actions would be completed, the patch is unlikely to be burdensome on the paramedic nor cause delay to patient care.
It may be considered that patients with opioid use disorder who have recently taken opioids are essentially having co-administration if a paramedic administers opioid analgesia. However, these patients typically require higher doses of opioids to achieve analgesia and, therefore, cannot be compared to patients who are opioid naïve. For patient safety, it is best to consult with a BHP before adding opioid analgesics, as is required by the analgesia medical directive.
Patient Care Standards:
Analgesia Medical Directive (ACP) > Clinical Considerations:
Fentanyl should not be used in combination with morphine unless authorised by BHP
Fleischman, RJ, et al, 2010. Effectiveness and Safety of Fentanyl Compared with Morphine for Out-of-Hospital Analgesia. Prehospital Emergency Care. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2924527/
Lexicomp, 2023. Fentanyl: Drug information. https://www.uptodate.com/contents/fentanyl-drug-information
Lexicomp, 2023. Morphine: Drug information. https://www.uptodate.com/contents/morphine-drug-information
Pandharipande, P. & Hayhurst, CJ, 2023. Pain control in the critically ill adult patient. UpToDate. https://www.uptodate.com/contents/pain-control-in-the-critically-ill-adult-patient
RPPEO, 2022. Should opioid analgesia be administered to a patient with opioid use disorder? MedicASK. https://www.rppeo.ca/paramedic-practice/medical-direction/medicask/medicask-answers-new/250-medical-directives/253-analgesia/1628-should-opioid-analgesia-be-administered-to-a-patient-with-opioid-use-disorder.html
Medical Directive Category
Please reference the MOST RECENT ALS PCS for updates and changes to these directives.