Premedication with intramuscular midazolam: a prospective randomized double-blind controlled study.

Abstract

One hundred A.S.A. physical status I and II surgical patients were randomized to receive midazolam, 0.07 mg/kg (group M, 31 patients), hydroxyzine, 1.0 mg/kg (group H, 34 patients), or midazolam diluent as a placebo (group P, 35 patients). Drugs were administered in the vastus lateralis muscle 60 to 90 minutes before anesthesia induction. Anesthesia was induced with thiopental, 3.0 mg/kg, followed by 1.0-mg/kg increments if required. An entry criterion was that patients score greater than or equal to 50% on a subjective Anxiety Visual Analog Test (AVAT). Anxiety was also objectively rated on a six-point scale by a trained observer. Patients and observer were unaware of type of premedication used. Midazolam and hydroxyzine produced significantly (p less than 0.05) greater reduction of anxiety than placebo on both the AVAT and objective anxiety evaluations. Peak onset appeared between 30 and 60 minutes after drug administration. Hemodynamic changes were similar in all groups, and no untoward reactions were encountered before anesthesia. The injection site 24 and 48 hours after administration showed evidence of mild tissue irritation in 68% of patients in group H, 26% of patients in group M, and none of the patients in group P. Midazolam is an efficacious, safe premedicant in relatively healthy patients. It has a prompt onset of action with only minimal tissue irritation.