Effects of age and gender on intravenous midazolam premedication: a randomized double-blind study

Background. Given the potentially important effects that age and gender may have on midazolam premedication, this study aimed at determining if these factors alter anxiety, sedation, and cardiorespiratory outcomes when administering two different doses of i.v. midazolam. Methods. After randomization, patients were premedicated 1 h before surgery with either i.v. midazolam 0.02 or 0.06 mg kg(-1) depending on their age and gender group. Levels of anxiety and sedation, heart rate, respiratory rate (RR), mean blood pressure (MBP), and oxygen saturation (Sp(O2)) were measured before and 15 min after midazolam administration. Results. A higher level of preoperative anxiety was more often observed in women than in men, and in young than in older patients. The female or younger patients showed significant anxiolytic benefits from midazolam. A deeper sedation level was found in men compared with women. Forty-two of 45 patients (93.3%) with excessive sedation received midazolam 0.06 mg kg(-1). The elderly patients receiving midazolam 0.06 mg kg(-1) showed significant reductions in MBP, RR, and Sp(O2). Of the patients with an Sp(O2) < 90%, 72.7% had received midazolam 0.06 mg kg(-1). Conclusions. Age and gender differences in neuropsychological and physiological responses after midazolam premedication were evident. Midazolam is effective for producing sedation and anxiolysis at a dose of 0.02 mg kg(-1), with minimal effects on cardiorespiration and oxygen saturation to patients. Dosage adjustments based on these covariates are, therefore, necessary.