The intravenous to oral relative milligram potency ratio of morphine during chronic dosing in cancer pain

Morphine (M) is the opioid analgesic of choice for severe cancer pain. The IV to PO M equipotent switch ratio (CR) is controversial. We designed this prospective observational cohort to confirm the efficacy and safety of M IV to PO CR of 1:3. Consecutive cancer patients admitted to an inpatient palliative medicine unit were screened for inclusion. Pain was managed by palliative medicine specialists. They were blinded to the patient data collected, and the calculated CR. The switch was considered successful if the following criteria were met: (1) Pain adequately controlled: pain rated as none or mild (2) Number of RD less than 4 (for non incident pain) per 24 hours (3) No limiting side effects. We used Day 3 ATC M dose for CR calculations. The major outcome measures were the IV : PO CR ratio, morphine doses (mg/day), pain severity, number of PRN doses, and day 1 and day 3side effects. Descriptive statistics were used to report mean, median, standard deviation and range of different variables. Two hundred a...