Comparison of the hemodynamic effects of midazolam and diazepam in patients with coronary occlusion.

Midazolam is gradually replacing diazepam in neuroleptanalgesia with fentanyl and sufentanil because of its greater water solubility, greater hypnotic potency, shorter half-life, lack of pharmacologically active metabolites and low incidence of thrombophlebitis. In order to substantiate midazolam as being as safe and effective as diazepam in cardiac patients with severe coronary occlusion, hemodynamic measurements were made before and 10 min after completion of intravenous injection of 0.2 mg/kg i.v. midazolam (n = 45) and 0.4 mg/kg i.v. diazepam (n = 30), the doses which are identical to those used in patients undergoing cardiac catheterization. All 75 patients were spontaneously breathing 40% O2 in air. No positional changes or stimulation of patients were allowed before and during the study. Of hemodynamic variables, systemic systolic blood pressure was significantly reduced by both midazolam and diazepam. Midazolam also caused significant reduction in systemic vascular resistance with reduction in diastolic pressure and left ventricular stroke work index. No changes in heart rate, systolic and diastolic pulmonary artery pressures, cardiac output and index, stroke volume and index, pulmonary vascular resistance, right ventricular stroke work index and rate pressure product were observed following either midazolam or diazepam. No statistically significant differences were observed in any hemodynamic variable between those patients receiving midazolam or diazepam. It is concluded that midazolam is as safe as diazepam in cardiac patients with coronary obstruction.