A randomised trial enrolled 1,194 emergency patients with acute musculoskeletal trauma and compared ketamine 20 mg intranasally with ketamine 20 mg subcutaneously. At 30 minutes the mean reduction on the numerical rating scale was 4.42 points intranasally and 3.70 subcutaneously, a difference of 0.72 with an interval from -0.95 to -0.48.
Statistically that excludes zero comfortably. Clinically it does not reach the 1.3-point threshold, and neither did the differences at any other time point. Secondary outcomes were the same apart from more minor adverse events in the subcutaneous arm.
The practical consequence is a genuine simplification. If the two routes produce equivalent analgesia at the same dose, the choice becomes which is faster to give, which the patient tolerates, and which the department can deliver without a needle — and intranasal wins all three for a distressed patient with a limb injury, a child, or anyone in whom vascular access is neither present nor needed. This is a trial whose null result expands what you can offer rather than restricting it.
- Same dose, 20 mg, by both routes — this is not a dose comparison
- Acute musculoskeletal trauma; not procedural sedation or chronic pain
- Slightly fewer minor adverse events with intranasal
- Removes the need for vascular access purely for analgesia
- Both arms achieved a 3.7 to 4.4 point reduction, which is substantial
The statistics, in plain English
A difference of 0.72 with an interval from -0.95 to -0.48 is statistically significant and clinically negligible — the entire interval sits below the 1.3-point minimum a patient can perceive. With 1,194 patients the trial had power to detect differences far smaller than anyone would act on, which is exactly when statistical significance stops being a useful guide on its own.
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