Maintenance time of sedative effects after an intravenous infusion of diazepam: A guide for endoscopy using diazepam

AIM: To examine whether the sedative effects assessed by psychomotor tests would depend on the cytochrome P450 (CYP ) 2C19 genotypes after an infusion regimen of diazepam commonly used forgastrointestinal endoscopy in Japan. METHODS: Fifteen healthy Japanese volunteers consisting of three different CYP2C19 genotype groups underwent a critical ? icker fusion test, an eye movement analysis and a postural sway test as a test for physical sedative effects, and a visual analog scale (VAS) symptom assessment method as a test for mental sedative effects during the 336 h period after the intravenous infusion of diazepam (5 mg). RESULTS: The physical sedative effects assessed by the critical flicker test continued for 1 h (t values of 5 min, 30 min and 60 min later: 4.35, 5.00 and 3.19, respectively) and those by the moving radial area of a postural sway test continued for 3 h (t values of 5 h, 30 h, 60 min and 3 h later: -4.05, -3.42, -2.17 and -2.58, respectively), which changed significantly compared with the baseline level before infusion (P < 0.05). On the other hand, the mental sedative effects by the VAS method improved within 1 h. The CYP2C19 genotype-dependent differences in the postinfusion sedative effects were not observed in any of the four psychomotor function tests. CONCLUSION: With the psychomotor tests, the objective sedative effects of diazepam continued for 1 h to 3 h irrespective of CYP2C19 genotype status and the subjective sedative symptoms improved within 1 h. Up to 3 h of clinical care appears to be required after the infusion of diazepam, although patients feel subjectively improved.