AS A HOSPITAL PHARMACIST, you’ll get more questions about safe use of IV ketamine as interest grows for a myriad of uses (acute pain, ICU sedation, etc). Ketamine may be a good option due to its potent analgesic and sedative effects, plus quick onset, short duration, and low cost. But ketamine can cause psychotic-like effects (hallucinations, etc), often called “emergence reactions,” since they may occur when emerging from anesthesia and can occur at lower ketamine doses.
Continue to save ketamine for when typical medications don’t work or aren’t the best fit, since evidence is often limited. Ensure you have protocols to guide ketamine use, including patient selection and hemodynamic and respiratory monitoring. For example, ketamine can bump up heart rate and blood pressure (BP). Avoid it if these increases could be risky, such as a patient with an acute MI or decompensated heart failure. And lean away from ketamine in schizophrenia, its psychotic-like effects may be more pronounced in these patients.
Help keep doses straight, since they vary widely by use, ensure monitoring intensity increases with dose and make certain it’s clear where ketamine can be given and by whom. Generally feel comfortable using low “sub-dissociative” ketamine doses, such as 0.1 to 0.3 mg/kg IV for acute pain in the emergency department (ED) or ICU with routine vital monitoring and continuous pulse oximetry.
Add ECG monitoring as doses step up, such as with a 0.5 mg/kg IV bolus followed by an infusion for ICU sedation. And restrict high ketamine doses in non-intubated patients. For example, if using 0.5 mg/kg for depression, consider a protocol similar to moderate-sedation, such as limiting who can order and administer ketamine and how long to monitor after the dose.
To reduce the risk of emergence reactions, infuse ketamine boluses slowly and provide a low-stimulus environment if possible. And tell clinicians to prepare patients by educating about the possible effects and to orient the patient as sedation wears off.
REFERENCES
Mo H, Campbell MJ, Fertel BS, Lam SW, Wells EJ, Casserly E, Meldon SW. Ketamine Safety and Use in the Emergency Department for Pain and Agitation/Delirium: A Health System Experience. West J Emerg Med. 2020 Jan 27;21(2):272-281. Available at: https://pubmed.ncbi.nlm.nih.gov/31999250
Nowacka A, Borczyk M. Ketamine applications beyond anesthesia - A literature review. Eur J Pharmacol. 2019 Oct 5;860:172547. Available at: https://pubmed.ncbi.nlm.nih.gov/31348905
Schwenk ES, Viscusi ER, Buvanendran A, Hurley RW, Wasan AD, Narouze S, Bhatia A, Davis FN, Hooten WM, Cohen SP. Consensus Guidelines on the Use of Intravenous Ketamine Infusions for Acute Pain Management From the American Society of Regional Anesthesia and Pain Medicine, the American Academy of Pain Medicine, and the American Society of Anesthesiologists. Reg Anesth Pain Med. 2018 Jul;43(5):456-466. Available at: https://pubmed.ncbi.nlm.nih.gov/29870457