Safety profile of prophylactic rescue dosing of immediate-release oral opioids in cancer patients

BACKGROUND: Appropriate prophylactic rescue dosing of opioids is considered effective for cancer pain relief, but no study has reported the safety of such prophylactic rescue. We compared the safety of prophylactic rescue dosing of immediate-release oral opioids with that of regular rescue dosing. METHODS: The study included 103 cancer patients who used either immediate-release morphine syrup or immediate-release oxycodone powder at Shizuoka Cancer Center between January and December 2016. Patients were divided into those who mostly used (prophylactic group) and those who never used (regular group) prophylactic rescue doses of opioids and compared the incidence of adverse events (AEs). We also investigated whether the prophylactic rescue dose negatively interfered with its objective activity, such as meals. RESULTS: Incidence of each AE in the prophylactic versus regular groups was as follows: somnolence, 20.6% versus 14.3%; nausea, 22.1% versus 17.1%; constipation, 19.1% versus 20.0%; urinary retention, 1.5% versus 2.9%; delirium, 4.4% versus 8.6%; and pruritus, 0% versus 2.9%. No serious AE associated with prophylactic rescue dosing was observed. No significant difference was observed in the incidence of any AE between the two groups (p > 0.05, Fisher’s exact test). No AE interfered with the objective activity of the prophylactic rescue dose. CONCLUSION: Incidence of AEs associated with prophylactic rescue dosing is not different from that associated with regular rescue dosing. In addition, the prophylactic rescue dose did not adversely affect its objective activity, suggesting the safety of appropriate prophylactic rescue dosing was similar to that of regular rescue dosing. TRIAL REGISTRATION: The study approval number in the institution; H29-J30–29–1-3. Registered June 5, 2017.