The cognitive and psychomotor effects of opioid analgesics

Abstract

Twelve subjects (3 male) took part in a randomised double-blind four way crossover study designed to examine the cognitive and psychomotor effects of single doses of dextroproxyphene. On four study days one week apart each subject received each study product (i) dextropropoxyphene napsylate 100 mg, (ii) dextropropoxyphene napsylate 200 mg, (iii) lorazepam 2 mg and (iv) placebo. Performance measures were simple reaction time, choice reaction time, number vigilance, memory scanning, word recall (immediate and delayed), word recognition, picture recognition, critical flicker fusion threshold (CFFT) and visual analogue scales of alertness, calmness and contentment. Lorazepam had a marked effect on the range of tests used illustrating the sensitivity of the best battery. This was in contrast to the effects of dextropropoxyphene. A dose related effect in CFFT was detected, the 200 mg dose producing a significant decrease in CFFT throughout the testing period. Dextropropoxyphene also showed a tendency to improve scores on the verbal memory tasks. These data indicate that dextropropoxyphene in the usual doses does not produce significant impairment of cognitive and psychomotor function.