The Use of Ketamine for Acute Treatment of Pain: A Randomized, Double-Blind, Placebo-Controlled Trial.

BACKGROUND: Pain is one of the most common reasons for emergency department (ED) visits in the United States. Ketamine is a sedative with N-methyl-D-aspartate (NMDA) receptor antagonism. Recent literature has suggested that the use of subdissociative dose ketamine (SDDK) may be safe and effective for acute pain.

OBJECTIVE: The objective of our study was to evaluate ketamine in subdissociative doses as an adjunct for acute pain in the ED.

METHODS: This was a single-center, prospective, randomized, double-blind, placebo-controlled trial that evaluated the use of SDDK in adult patients who presented to the ED with acute pain. Patients received ketamine 0.3 mg/kg via intravenous piggyback over 15 min or placebo. Morphine 0.1 mg/kg intravenous push was administered with the study interventions. The primary outcome was the patient's pain score 15 min after initiation of the intervention. Secondary outcomes included adverse events, consumption of rescue analgesia, patient's length of stay, and patient satisfaction with treatment.

RESULTS: Thirty patients were enrolled in each group. Median pain scores in patients who received ketamine were lower than in controls at 15 min (3.5 [interquartile range {IQR} 1.0-7.3 vs. 6.0 [IQR 4.0-9.0], respectively; p = 0.018). No serious adverse events occurred. No difference was detected in the amount of rescue analgesia used or in length of stay. Patients who received ketamine reported a higher mean satisfaction score with their pain management (8.57 [standard deviation {SD} 2.1]) than patients who received placebo (6.05 [SD 2.6]; p = 0.01).

CONCLUSION: When used as an adjunct, SDDK administered at 0.3 mg/kg over 15 min resulted in safe and effective analgesia for ≤30 min in patients who presented with acute pain in the ED.