Introduction: Oral mucositis is a painful side effect to chemotherapy. Orally applied opioids may offer analgesia with fewer side effects than systemic opioids.

Methods: A randomized trial comparing the analgesic effect of a morphine oromucosal solution (OM) to placebo and a positive control group receiving intravenous (IV) morphine as an add-on treatment to morphine patient-controlled analgesia (PCA) in a mixed population of paediatric and adult haematology patients. All patients in the study were equipped with a morphine PCA pump and the participating patients were instructed to use this pump as an escape. Primary outcome was morphine consumption (mg/kg/hour) on the PCA pump. Secondary outcomes included pain intensity difference at rest and when performing oral hygiene, time to first PCA bolus, nutrition intake and adverse events.

Findings: A total of 60 patients (38 children

Conclusion: The findings indicate that the analgesic effect of peripherally applied morphine is not significantly different from placebo, and parenteral opioids should continue to be the standard of care.