Randomized controlled trial of midazolam premedication to reduce the subjective adverse effects of adenosine

To determine the safety and efficacy of midazolam premedication to minimize the subjective adverse effects of adenosine.

Double-blind prospective randomized controlled trial of patients presenting to an urban emergency department. Included were a convenience sample of patients who would have received adenosine by the existing department protocol. Exclusion criteria were pregnancy, benzodiazepine allergy, regular benzodiazepine medication, alcoholism, altered mental state (precluding informed consent), and age less than 18 or greater than 65 years. Subjects received either 1.5 mg of intravenous midazolam or normal saline placebo 5 min prior to the administration of adenosine. Side-effect recall was judged by a questionnaire at 1 h and 24 h postadenosine administration.

A total of 34 patients were recruited into the trial, 16 in the placebo group and 18 in the midazolam group. The groups were well matched for demographics, treatment and outcome. There was a significant reduction in the midazolam group for complaint scores of palpitations (P = 0.04) and chest pain (P = 0.02) and a trend to reduction in complaint scores for most other parameters. There were no adverse outcomes in any of the patients studied.

Co-administration of midazolam can safely reduce the recall of the unpleasant adverse effects of adenosine. Its use may be most appropriate in patients who are particularly anxious or have had previous adverse experiences with adenosine.