The Effect of Low-Dose Ketamine in Treating Acute Asthma Attack; a Randomized Clinical Trial

Efficient treatment of asthma can play an important role in controlling asthma attacks, rapid recovery and decrease of patient mortality. Therefore, in the present study the therapeutic effect of low-dose ketamine is evaluated in patients with acute asthma attack. In the present single-blind, randomized clinical trial with placebo control, the effect of low-dose intravenous ketamine in treating 18 to 85 year-old asthmatic patients who presented to the emergency department was evaluated. Peak expiratory flow rate (PEFR) and the patients’ response to treatment were measured before and 1 hour after treatment. Additionally, using SPSS 22.0, effectiveness of ketamine with 0.3, 0.4, and 0.5 mg/kg doses followed by infusion of the same dose during 30 minutes were compared with placebo. 92 patients were enrolled (59.8% female, mean age 48.5 ± 13.9 years). 15 (16.3%) patients were treated with 0.3 mg/kg ketamine, 14 (15.2%) with 0.4 mg/kg, and 16 (17.4%) with 0.5 mg/kg doses. Mean PEFR was 336.2 ± 101.5 liters in the placebo group and 345.8 ± 84.7 liters in the ketamine group before intervention (p = 0.6), while after intervention, they were 352.1 ± 101.2 and 415.8 ± 76.2 liters, respectively (p = 0.001). Ketamine treatment with 0.4 and 0.5 mg/kg doses led to a higher increase in PEFR compared to 0.3mg/kg dose (df: 3, 88; F = 23.8; p < 0.001). It seems that administration of 0.4 - 0.5 mg/kg doses of intravenous ketamine followed by infusion of the same dose during 30 minutes can be effective for rapid recovery of PEFR in patients with mild to moderate asthma.