Double-blind randomized controlled trial to determine extent of amnesia with midazolam given immediately before general anaesthesia.

Abstract

BACKGROUND:

Anterograde, but not retrograde, amnesia has been demonstrated following midazolam administration. However, there have been no studies investigating whether or not immediate retrograde amnesia can be produced with midazolam.

METHODS:

After ethics committee approval and consent, 40 adult patients undergoing surgery and general anaesthesia were randomly allocated to one of four groups: midazolam 2 mg, midazolam 5 mg, midazolam 10 mg or control (normal saline). Measurements were made from 12 min prior to induction of anaesthesia, and the study drug was administered 8 min prior to induction of anaesthesia. Midazolam effects were measured using visual recognition of posters, recall of specific events, bispectral index (BIS) and sedation visual analogue score.

RESULTS:

Recognition and recall rates were similar between groups up until the time of study drug administration, with no evidence of retrograde amnesia (all P>0.3). There was a dose-dependent deterioration in visual recall (P=0.002), event recollection (P<0.001), BIS (P<0.001) and sedation score (P<0.001) following i.v. midazolam when compared with control.

CONCLUSIONS:

We found no evidence that i.v. midazolam 2-10 mg produces immediate retrograde amnesia. Midazolam causes anterograde amnesia in a dose-responsive manner.

• Authors: R Bulach, P S Myles, M Russnak
• Journal: British journal of anaesthesia (Br J Anaesth) Vol. 94 Issue 3 Pg. 300-5 (Mar 2005) ISSN: 0007-0912 [Print] England
• PMID: 15567810 (Publication Type: Clinical Trial, Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Hypnotics and Sedatives
• Midazolam

Topics

• Adult
• Amnesia, Retrograde (chemically induced)
• Anesthesia, General
• Conscious Sedation (methods)
• Dose-Response Relationship, Drug
• Double-Blind Method
• Electroencephalography (drug effects)
• Humans
• Hypnotics and Sedatives (pharmacology)
• Mental Recall (drug effects)
• Midazolam (pharmacology)
• Middle Aged
• Preanesthetic Medication
• Recognition, Psychology (drug effects)