P. Sjogren et al., CONTINUOUS REACTION-TIME AFTER SINGLE-DOSE, LONG-TERM ORAL AND EPIDURAL OPIOID ADMINISTRATION, European journal of anaesthesiology, 11(2), 1994, pp. 95-100
Auditory continuous reaction time was studied in three treatment group
s. Twenty opioid naive patients received intramuscular morphine 0.1 5
mg kg-1 bodyweight for premedication. Thirty-one cancer patients were
treated with oral opioids, 180 mg morphine per 24 h (median). Twenty-t
wo cancer patients were treated with epidural morphine, 79 mg morphine
per 24 h (median). The treatment groups were compared to a control gr
oup of 44 healthy persons taking no analgesics. The reaction time was
measured using 152 auditory signals and summarized as 10%, 50% and 90%
percentiles. Analysing reaction time distributions, the opioid naive
patients showed the greatest difference to the control group in the sh
ortest reaction times while chronic opioid users showed the greatest d
ifference for the longest reaction times. There seems to be a qualitat
ive difference in reaction time distribution, between opioid naive ind
ividuals treated with single dose morphine and cancer patients in long
-term treatment.