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Pain Dose Ketamine – What Dose is Best?

February 23, 2021

Written by Aaron Lacy.

With special thanks to Erica Koch, VUMC EM resident, who was a co-author of this study and who also reviewed this summary!

Spoon Feed
In patients given pain dose IV sub-dissociative ketamine, a lower dose (0.15mg/kg) was non-inferior to a higher dose (0.30mg/kg) for pain relief at 30 minutes and had fewer adverse effects.

Why does this matter?
As we strive toward opioid alternatives for acute pain treatment, ketamine has been proven in multiple studies to be non-inferior to opiate pain medication. But ketamine, like all medications, is not without adverse effects. We know that adverse effects are proportional to dosing in ketamine, so what is the sweet spot for balancing pain relief and adverse effects?

The only medicine that works for my pain is that one that starts with a K…
Patients aged 18-59 presenting with acute, moderate to severe pain were randomized prospectively to either administration of 0.15 mg/kg (low dose) versus 0.30 mg/kg (high dose) of IV ketamine given over 15 minutes. Patients and providers were blinded to dose, and primary outcome was pain on the 11-point numerical ratings scale (NRS) at 30 minutes. Pain relief in the low dose group was non-inferior (NRS 4.7, 95%CI 3.8-5.5) to the high dose group (NRS 5.0, 95%CI 4.2-5.8). Adverse effects were similar at 30 minutes. At 15 minutes, the high dose group had a greater decrease in pain on the NRS but had more adverse events. Overall, patients generally reported that they would take ketamine again for a similar indication (75.6% in low dose group, 61.7% in high dose group).

In this small study, IV ketamine, just like another popular alternative analgesic to opioids, ketorolac, seemed to have no increase in pain relief with increasing doses.  Going forward, I plan to start low with my ketamine dose for acute pain.

A Randomized, Non-Inferiority, Controlled Trial of Two Doses of Intravenous Sub-Dissociative Ketamine for Analgesia in the Emergency Department. Acad Emerg Med. 2020 Dec 22. doi: 10.1111/acem.14200. Online ahead of print.

One thought on “Pain Dose Ketamine – What Dose is Best?

  • Isn’t the spoon feed is misleading? Adverse effects were the same at 30 minutes. Per the paper’s conclusion: Our data did not detect a large difference in analgesia or adverse effect profile between 0.15 mg/kg IV ketamine and 0.30 mg/kg in the short-term treatment of acute pain in the ED. Trying to get access to the full paper and will be most interested in how "small" this study was.

What are your thoughts?