Studies on psychomotor performance in healthy volunteers after diazepam, propranolol and alcohol given alone or in combination.

The effects of diazepam, propranolol or alcohol alone or in combination with each other were examined in ten normal healthy volunteers on tests of psychomotor function. Results showed impaired psychomotor performance persisting upto 4-5 h when the aforementioned agents given singly were tested on simple reaction time (SRT), multiple choice reaction time (MCRT) and critical flicker fusion frequency (CFFF) tasks. Digit cancellation task (DCT) was similarly affected by diazepam and alcohol only. No summation of adverse effects on psychomotor performance was noted when a combination of diazepam and alcohol, diazepam-propranol or alcohol plus propranolol were tested on SRT and MCRT. An additive impairment of CFFF was observed with alcohol - propranolol combination only. No summation of pharmacodynamic effects on DCT were noted when different combinations were used.