Comparative cardiovascular effects of midazolam and thiopental in healthy patients

Anesth Analg. 1982 Sep;61(9):771-5.


Midazolam, a water-soluble benzodiazepine that is shorter-acting, more potent, and less irritating to veins than diazepam, has been suggested for use for induction of anesthesia. The cardiovascular effects of an induction-sized dose (0.25 mg/kg) of midazolam in A.S.A. class I or II surgical patients (N = 11) sedated with morphine and N2O-O2 were compared in a double-blind fashion with a similar group of patients (N = 9) receiving thiopental (4.0 mg/kg). Consistent with earlier studies, patients given thiopental experienced downward trends from base line in mean arterial pressure, stroke volume, cardiac output, and heart rate; mean right atrial pressure increased slightly, whereas systemic vascular resistance did not change. Induction of anesthesia with midazolam was associated with more gradual and less pronounced hemodynamic alteration; the only significant changes from base line were decreases in mean arterial pressure 5 and 10 minutes after injection. When the two groups were compared, no significant differences were found. Midazolam is, then, as acceptable for induction of anesthesia as thiopental from a hemodynamic point of view in A.S.A. class I and II patients.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Anesthetics / pharmacology*
  • Benzodiazepines / pharmacology*
  • Blood Pressure / drug effects
  • Cardiac Output / drug effects
  • Double-Blind Method
  • Female
  • Heart Atria / drug effects
  • Heart Rate / drug effects
  • Hemodynamics / drug effects*
  • Humans
  • Male
  • Midazolam
  • Middle Aged
  • Pressure
  • Stroke Volume / drug effects
  • Thiopental / pharmacology*
  • Vascular Resistance / drug effects


  • Anesthetics
  • Benzodiazepines
  • Thiopental
  • Midazolam