Circadian distribution of extra doses of narcotic analgesics in patients with cancer pain: a preliminary report.

In this open study we reviewed the circadian distribution of extra doses of narcotic analgesics in 61 bed-ridden patients with cancer pain. The information was collected prospectively and retrospectively in 34 and 27 cases, respectively. All patients were receiving parenteral narcotics using the Edmonton Injector, and none had incidental pain or cognitive impairment. A total of 1322 extra doses of narcotics (each dose = 10% of the daily dose) were administered during 610 patient days (average of 2.17 +/- 1.6 doses/patient/day). The mean daily number of extra doses during each interval was as follows: 02.00-06.00 h (0.24 +/- 0.27), 06.00-10.00 h (0.26 +/- 0.31), 10.00-14.00 h (0.43 +/- 0.44), 14.00-18.00 h (0.44 +/- 0.41), 18.00-22.00 h (0.40 +/- 0.36), and 22.00-02.00 h (0.40 +/- 0.36) (02.00-06.00 h and 06.00-10.00 h vs. 10.00-02.00 h: P less than 0.01). Forty-five of 61 patients (76%) received most of their extra doses of narcotics between 10.00 and 22.00 h. The data suggest that our patients require a larger number of extra doses during day time. Our design cannot establish the reason for this circadian variation.