This randomized double-blind controlled study determined the minimum dose of intravenous midazolam that caused anterograde amnesia in 50 percent of adult Filipino subjects of different age groups. It also determined the relationship between the required and actual doses of midazolam and the resultant amnesia with factors of weight, age, sex and duration of anesthesia as controls. A total of 150 patients scheduled for different surgeries and procedures were divided according to three age groups: A=20-39 yr, 6=40-59 yr, and C=60-79 yr. The groups were further subdivided according to five midazolam dosages: 0.01,0.02,0.03,0.04 and 0.05mg/kg. Colored geometric cards were shown to the patients before and three minutes after giving intravenous midazolam. Post-operatively, recall and recognition of the cards were assessed. Using Probit analysis, the ED50 values of midazolam for groups A, B and C were 0.023 mg/kg, 0.020 mg/kg and 0.017 mg/kg, respectively. Based on the results, the required dose seemed to be a better predictor of amnesia than the actual dose. Age, sex and to a lesser extent, the weight of the patient but not the duration of the procedure were found to influence resultant amnesia. Because of the possibility of gender influencing midazolam-induced amnesia, it is recommended that future studies be made among Filipino subjects using gender as a controlled variable. Other variables that should be considered are the level of anxiety and the level of sedation of the patients. (Author)
1) To determine the minimum dose of intravenous midazolam that can cause anterograde amnesia in 50% of adult Filipino subjects of ages 20-39 years, 40-59 years and 60-79 years and;
2) To determine the relationship of the required and actual doses of midazolam and the resultant amnesia using factors of weight, age, sex, and duration of anesthesia as controls.