Written by Clay Smith
Pretreatment with either midazolam or haloperidol prior to ketamine sedation markedly reduced the risk of recovery agitation but delayed recovery time by about 20-30 minutes.
Why does this matter?
Recovery agitation, a.k.a. emergence reaction, after sedation with ketamine can be frightening for patients. If you’ve seen it before, you’ll know it can be quite impressive. I have seen some whooping and hollerin’. Where I live, people sometimes say “holler,” which means – to yell very loudly, vociferate, shriek, call out. It can also mean a small valley between two hills, as in, “We live down in the holler.” Anyway, blunting this adverse effect might be good.
Preventing post-ketamine cray-cray
This was a multifactorial RCT comparing placebo, midazolam 0.05mg/kg IV, or haloperidol 5mg IV pretreatment to prevent recovery agitation after ketamine sedation in the ED. They enrolled 185 patients and found that on validated agitation scales, recovery agitation was significantly less. Both midazolam and haloperidol were 3 points lower than placebo on the agitation scale. The downside was that recovery was delayed: 18 minutes, placebo; 35 minutes, midazolam; 50 minutes, haloperidol. Despite the delay, it did not seem to impact clinician satisfaction with the overall sedation. Recovery agitation occurred in 64% of the placebo group, which seems a bit high. It occurred in only 25% of the midazolam patients and 20% of the haloperidol patients; relative risk reduction 61-69%. The guide to all things ketamine by Reuben Strayer found emergence reaction occurred in 10-20% of patients. However, I tend to think this study is credible since they measured it with the validated Pittsburgh Agitation Scale, whereas other studies have used visual analog scales or other non-validated scores to measure agitation. Clinically significant, disruptive behaviors occurred in 26.2% in the placebo group, and were also markedly reduced in the midazolam and haloperidol groups.
If you want a great read on the adverse effects of ketamine in adults, Reuben Strayer has the comprehensive guide.
Premedication With Midazolam or Haloperidol to Prevent Recovery Agitation in Adults Undergoing Procedural Sedation With Ketamine: A Randomized Double-Blind Clinical Trial. Ann Emerg Med. 2019 Jan 3. pii: S0196-0644(18)31465-3. doi: 10.1016/j.annemergmed.2018.11.016. [Epub ahead of print]
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Reviewed by Thomas Davis