Oral oxycodone could be an important analgaesic agent for the management of postoperative pain in hospitalised patients with moderate to severe pain ( greater than 40 mm on the visual analog scale [VAS]), according to results of a double-blind study.
When oxycodone hydrochloride capsules and morphine sulfate tablets were compared at a dose ratio of 1:2, oxycodone was comparable to morphine in terms of efficacy and safety, stated lead author Xinmin Wu, MD, Peking University First Hospital, Beijing, China.
Dr. Wu and colleagues included postoperative hospitalised patients with moderate to severe pain from 5 centres, and randomised them into 2 groups. The first group received oral oxycodone hydrochloride capsules 10 mg; the second group received morphine sulfate tablets 20 mg. A total of 230 patients completed the study. Doses were given once every 6 hours for 24 hours. The surgeries were mostly laparoscopic (68%), which is associated with a lesser pain intensity than open surgery.
Resting and coughing VAS scores were obtained at 0 hours (baseline), 0.5 hours ± 5 minutes after first dose, 2 hours ± 10 min, 6 hours ± 20 minutes, 12 hours ± 20 minutes, 18 hours ± 20 minutes and 24 hours ± 20 minutes. Intramuscular pethidine 50 mg/dose was used as rescue medication. VAS scores were first obtained during rest at 6 hours (between the first and second dose). Secondary endpoints were VAS scores during cough at 6 hours; use of rescue medication at 24 hours; comparison of mean resting VAS and VAS during cough at 0.5, 2, and 24 hours; evaluation of sleep; patient satisfaction; and comparison of overall use of study drugs within 24 hours.
Baseline VAS scores were 46.21 mm for the oxycodone group and 45.48 mm for the morphine group, decreasing to 20.21 mm and 19.94 mm, respectively, at rest, at 6 hours. Additionally, there was no significant difference in pain scores between the groups during cough at 6 hours, for use of pethidine, or for sleep quality.
The mean ratio of oxycodone capsules to morphine tablets consumed by patients with VAS less than 70 mm was 18.90 mg to 38.74 mg (about 1:2); the mean ratio in patients with VAS greater than 70 mm was 23.75 mg to 60.00 (about 1:2.5).
The incidence of adverse events (AEs) related to the study drug was 15.38% for oxycodone and 11.97% for morphine. There were no serious AEs, and none resulted in discontinuation of either analgaesic. The most common AEs were the same for both groups: nausea (12.82% for the oxycodone group vs 11.97% for the morphine group), vomiting (5.98% for both), and dizziness (5.98% vs 5.13%, respectively).
Demographic data and baseline VAS scores were similar for both groups.