Pharmacokinetics and sedative effect of midazolam in connection with caesarean section performed under epidural analgesia

Acta Anaesthesiol Scand. 1984 Feb;28(1):116-8. doi: 10.1111/j.1399-6576.1984.tb02024.x.


Midazolam, the new investigational 1,4-benzodiazepine derivative with highly water-soluble salts, was studied as an anaesthesiological adjuvant in 11 patients undergoing elective caeserean section under epidural analgesia. I.v. administered midazolam, 0.075 mg/kg after delivery, caused a rapid and marked sedative effect, lasting for about 2-3 h. Short-lasting anterograde amnesia of about 30 to 60 min was reported as well. The serum levels of the parent drug and its active metabolites were determined in six cases by a radioreceptor assay and pharmacokinetic parameters were calculated on the basis of these levels by a two-compartment open model. Up to 3 h after midazolam administration, good correlation between the sedative effect and serum drug levels was found. The rapid but short-lasting action can be explained by the pharmacokinetic parameters of midazolam: a short distribution phase half-life (4.19 min), and a short elimination phase half-life (67.85 min) due to a high clearance value (13.18 ml/min/kg) and a moderate distribution volume (1.20 l/kg).

MeSH terms

  • Adult
  • Analgesics* / metabolism
  • Anesthesia, Epidural
  • Anesthesia, Obstetrical*
  • Benzodiazepines* / metabolism
  • Cesarean Section*
  • Female
  • Half-Life
  • Humans
  • Kinetics
  • Midazolam
  • Preanesthetic Medication*
  • Pregnancy
  • Time Factors


  • Analgesics
  • Benzodiazepines
  • Midazolam