Comparison of Intramuscular Betamethasone and Oral Pprednisone in the Prevention of Relapse of Acute Asthma

Abstract

OBJECTIVE: To compare the relapse rate after a single intramuscular injection of a long acting corticosteroid, betamethasone, with oral prednisone in patients discharged from the emergency department (ED) for acute exacerbations of asthma.PATIENTS AND METHODS: Patients with acute exacerbations of asthma who were suitable for discharge from the ED were enrolled in a double-blind, randomized, placebo controlled pilot study. At discharge, patients were randomly assigned to receive either intramuscular betamethasone 12 mg and placebo capsules, or a placebo intramuscular injection and prednisone 50 mg daily for seven days. At days 7 and 21, patients were contacted by telephone to determine relapse. Relapse was defined as an unscheduled visit to a physician for treatment of continuing or worsening symptoms of asthma.RESULTS: One hundred and seventy-one patients were enrolled, of whom 87 were randomly assigned to the betamethasone group and 84 to the prednisone group. Baseline char- acteristics were matched evenly between the groups, with the exception of asthma duration (15.5 versus 21.2 years, respectively) and use of inhaled corticosteroids (46% versus 64.3% respectively) (P<0.05). Using intention-to-treat analysis, the relapse rates for betamethasone and prednisone at day 7 were 14.9% (13 of 87 patients) and 25% (21 of 84 patients), respectively (P=0.1), and at day 21, the rates were 36.8% (32 of 87 patients) and 31% (26 of 84 patients), respectively (P=0.4). There were no differences in symptom score, peak flows and adverse effects between the two groups at days 7 and 21.CONCLUSIONS: A single dose of intramuscular betamethasone 12 mg was safe and as efficacious as prednisone in preventing the relapse of acute asthma. There was a trend toward a reduced relapse rate at seven days. In select ED patients discharged for acute asthma, intramuscular betamethasone may be an effective alternative to prednisone.