DRIVING ABILITY IN CANCER-PATIENTS RECEIVING LONG-TERM MORPHINE ANALGESIA

When given in single doses to healthy volunteers, opioid analgesics im pair reaction time, muscle coordination, attention, and short-term mem ory sufficiently to affect driving and other skilled activities. Despi te the increasing use of oral morphine daily, little is known about th e effect of long-term opioid therapy on psychomotor performance. To ex amine the effects of continuous morphine medication, psychological and neurological tests originally designed for professional motor vehicle drivers were conducted in two groups of cancer patients who were simi lar apart from experience of pain, 24 were on continuous morphine (mea n 209 mg oral morphine daily) for cancer pain; and 25 were pain-free w ithout regular analgesics. Though the results were a little worse in t he patients taking morphine, there were no significant differences bet ween the groups in intelligence, vigilance. concentration, fluency of motor reactions, or division of attention. Of the neural function test s, reaction times (auditory, visual, associative), thermal discriminat ion, and body sway with eyes open were similar in the two groups; only balancing ability with closed eyes was worse in the morphine group. T hese results indicate that, in cancer patients receiving long-term mor phine treatment with stable doses, morphine has only a slight and sele ctive effect on functions related to driving.