Episode 900: Ketamine Dosing

Contributor: Travis Barlock MD

Educational Pearls:

Ketamine is an NMDA receptor antagonist with a wide variety of uses in the emergency department. To dose ketamine remember the numbers 0.3, 1, and 3.

Pain dose

• For acute pain relief administer 0.3 mg/kg of ketamine IV over 10-20 minutes (max of 30 mg).

• Note: There is evidence that a lower dose of 0.1-0.15 mg/kg can be just as effective.

Dissociative dose

• To use ketamine as an induction agent for intubation or for procedural sedation administer 1 mg/kg IV over 1-2 minutes.

IM for acute agitation

• If a patient is out of control and a danger to themselves or others, administer 3 mg/kg intramuscularly (max 500 mg).

• If you are giving IM ketamine it has to be in the concentrated 100 mg/ml vial.

Additional pearls

• Pushing ketamine too quickly can cause laryngospasm.

• Between .3 and 1 mg/kg is known as the recreational dose. You want to avoid this range because this is where ketamine starts to pick up its dissociative effects and can cause unpleasant and intense hallucinations. This is colloquially known as being in the "k-hole".

References

1. Gao, M., Rejaei, D., & Liu, H. (2016). Ketamine use in current clinical practice. Acta pharmacologica Sinica, 37(7), 865–872. https://doi.org/10.1038/aps.2016.5

2. Lin, J., Figuerado, Y., Montgomery, A., Lee, J., Cannis, M., Norton, V. C., Calvo, R., & Sikand, H. (2021). Efficacy of ketamine for initial control of acute agitation in the emergency department: A randomized study. The American journal of emergency medicine, 44, 306–311. https://doi.org/10.1016/j.ajem.2020.04.013

3. Stirling, J., & McCoy, L. (2010). Quantifying the psychological effects of ketamine: from euphoria to the k-Hole. Substance use & misuse, 45(14), 2428–2443. https://doi.org/10.3109/10826081003793912

Summarized by Jeffrey Olson MS2 | Edited by Jorge Chalit, OMS II