BACKGROUND. The use of oxycodone to treat chronic cancer pain has been hampered by its short elimination half-life, which necessitates administration every 4 hours. This study compared the clinical efficacy and safety of a novel oxycodone formulation with that of hydromorphone in the treatment of cancer pain. METHODS. In a double-blind crossover study, 44 patients with stable cancer pain were randomized to controlled-release oxycodone or controlled-release hydromorphone, each given every 12 hours for 7 days. Pain intensity, nausea, and sedation were assessed by patients four times daily, and breakthrough analgesia was recorded. RESULTS. Thirty-one patients completed the study (18 women, 13 men; mean age, 56 +/- 3 years) and received a final controlled-release oxycodone dose of 124 +/- 22 mg per day and a final controlled-release hydromorphone dose of 30 +/- 6 mg per day. There were no significant differences between treatments in overall Visual Analogue Scale (VAS) pain intensity (VAS 28 +/- 4 mm vs, 31 +/- 4 mm), categorical pain intensity (1.4 +/- 0.1 vs. 1.5 +/- 0.1), daily rescue analgesic consumption (1.4 +/- 0.3 vs. 1.6 +/- 0.3), sedation scores (24 +/- 4 mm vs. 18 +/- 3 mm), nausea scores (15 +/- 3 mm vs. 13 +/- 3 mm), or patient preference, Two patients experienced hallucinations on controlled-release hydromorphone, but none did while receiving controlled-release oxycodone. CONCLUSIONS. Controlled-release oxycodone demonstrated excellent pharmacodynamic characteristics, analgesic efficacy, and safety as compared with controlled-release hydromorphone and represents an important new therapeutic option for cancer pain management. (C) 1997 American Cancer Society.