Circadian distribution of oral opioid consumption in cancer patients

Diurnal variations are reported in pain perception, potency of placebo and in the pharmacokinetics of morphine. It is not established if such diurnal variation should be reflected in the routine prescription of analgesic drug s to cancer patients. One approach for investigating this question is to st udy the circadian rhythm of patients' requests for analgesics. We included 40 patients with malignant disease and intolerable pain despite treatment w ith weak opioids. Weak opioids were stopped and the patients' pain treatmen t was restricted for the next 2 days to strong oral opioids (ketobemidone) given on an as-needed basis. The number and times of all ketobemidone admin istrations were recorded. No significant diurnal variation in use of ketobe midone was observed. A descriptive curve that interpolates between successi ve observations displayed only slight circadian fluctuations of opioid cons umption. Thus, the data reported in this paper does not support the necessi ty of considering chronopharmacological factors in the routine prescription of oral opioids. (C) 2000 Prous Science. All rights reserved.