Influence of changes to daily dose of opioids on aspects of cognitive and psychomotor performance involved in driving

Introduction. It has been shown that long-term treatment with opioids does not necessarily impair driving ability in patients suffering from chronic pain. However, few studies are so far available on how increases in daily opioid dosage affect driving ability. Methods. A prospective trial was conducted in patients suffering from chronic noncancer pain, to examine the effects of the daily dose of opioids on psychomotor and cognitive functions. A computerized test system was administered to patients before and 7 days after alteration of their opioid therapy, to determine performance affecting driving ability at each time point. The test design was based on both international and national recommendations for the examination of driving safety. Results. Raising the daily dose of opioids and/or changing to an opioid at a higher WHO level had no effect on the functions relevant to driving ability in the group context. Pain intensity and serum concentrations of morphine influenced only few items in the test battery. Conclusion. Seven days after an increase in the daily dose of an opioid or after the initiation of opioid therapy there was no general deterioration in patients' driving ability at group level.