Reasons for discontinuation of acute postoperative pain ketamine infusions: A retrospective case-control study.

Patients who required discontinuation of their low-dose ketamine infusion due to ADEs were more likely to be opioid naïve, received less pre-operative benzodiazepines, and had greater postoperative opioid PCA requirements. Control patients, on the other hand, had higher rates of pre-operative opioid use and experienced fewer ADEs despite greater total ketamine doses.