Intravenous morphine consumption in outpatients with cancer during their last week of life--an analysis based on patient-controlled analgesia data.

INTRODUCTION: Studies on opioid use in terminally ill cancer patients have shown a prefinal dose increase in the majority of patients. Mostly oral opioids were used. Due to the pharmacokinetic properties of opioids, it is rather difficult to get a reliable estimate of the true opioid need from those results.
MATERIALS AND METHODS: Retrospectively, we analyzed opioid use during the last week of life of 30 consecutive outpatients with cancer on intravenous (i.v.) morphine patient-controlled analgesia (PCA). A dose increase (decrease) was defined as an increase (decrease) of the patient's individual daily dose by at least 30% with respect to their prior daily dose. We also analyzed circadian variations in morphine use.
RESULTS: Thirty patients fulfilled the primary study inclusion criteria. Fulfilling the exclusion criteria, seven patients had to be excluded from analysis (n = 3, on PCA for less than 7 days; n = 4, PCA was finished before death). Twenty-three patients with a total of 161 treatment days were analyzed. The patients' median age was 57 years (range, 4 to 72). The median duration of intravenous morphine PCA was 19 days (range, 8 to 58). The median daily intravenous morphine dose during the last week of life was 96 to 115 mg, without significant change over time/from day to day (Friedman test). On 144/161 days (89.2%), morphine dose remained stable. On 9 treatment days (5.6%), the dose increased, and on 8 days (5.0%), it decreased. In three patients, only dose increases, and in four patients, only dose decreases were observed. In four patients, both dose increases and decreases were observed. Twelve patients showed no change in daily morphine dose. Opioid use lacked a diurnal pattern.
CONCLUSION: During their end-of-life phase, cancer patients on i.v. morphine PCA showed a stable daily opioid need.