Ketamine

Two high quality studies (Remerand 2009, Cengiz 2014) demonstrated that peri-operative intravenous ketamine was associated with less morphine use in the first 24 hours after THA & TKA respectively.

Benefits/Harms of Implementation

Reducing opioid use in the post-op period mitigates their well-known side-effects such as nausea/vomiting, respiratory depression, tolerance, etc. Ketamine can produce many side-effects however they are mostly associated with anesthetic-level dosing. Low-dose, i.e. sub-anesthetic, ketamine used as an adjunct pain medicine has been associated with vivid dreams and hallucinations.

Outcome Importance

The US is in the midst of an opioid epidemic known to contribute to the development of hyperalgesia, tolerance, dependence, addiction, and abuse. Therefore, reducing opioid use is a national priority.

Cost Effectiveness/Resource Utilization

Ketamine is an inexpensive, generic medication on the WHO Model List of Essential Medicines, 21^st List (2019). The peri-operative use of ketamine requires the assistance of a qualified anesthesia provider.

Acceptability

Ketamine is already widely used as an adjunctive pain medicine for patients undergoing surgery.

Feasibility

Intravenous ketamine can be easily administered by intermittent manual bolus, gravity infusion, or mechanical pump infusion.

Future Research

Ketamine is an NMDA receptor antagonist, and the NMDA receptor is the nexus of pathways leading to hyperalgesia from poorly controlled pain and opioid use. Future studies should explore longer term outcomes associated with the perioperative use of ketamine such as the development of chronic pain, persistent opioid use, and opioid use disorder.