ABSTRACT
Background: Hydromorphone is an analogue of morphine used in the treatment of cancer-related pain. There have been few studies that have evaluated the analgesic effect upon transition from hydromorphone injections. The aim of this study was to evaluate the conversion ratio between injection and oral preparation. Methods: We conducted a retrospective chart study of consecutive patients who were admitted to our hospital between July 2018 and December 2019. Results: In six patients, when the conversion ratio from hydromorphone injection to oral was changed at a 1:5 conversion ratio, three patients obtained adequate analgesic effects, the analgesic effect was insufficient in one case and an increased dose was required. Significant drowsiness appeared in two patients who required a decrease in dose. Conclusions: In converting from hydromorphone injections to oral preparations, it is necessary to carefully monitor the analgesic effect and adverse events and adjust the dosage for each case regardless of the conversion ratio.