Members of 3 separate governing bodies — the American Society of Regional Anesthesia and Pain Medicine, the American Academy of Pain Medicine, and the American Society of Anesthesiologists — approved consensus guidelines regarding the use of ketamine for the management of acute pain, according to a report in Regional Anesthesia and Pain Medicine. The recommendations include guidance on 6 key points regarding ketamine, spanning a range of clinical concerns, and were a follow-up to recently issued chronic pain guidelines.
Ketamine infusions — which have been used selectively for decades — have garnered recent interest in the face of the national opioid epidemic, particularly in emergency departments, perioperatively, and in individuals with opioid tolerance. However, little formal guidance has been offered, leaving clinicians with unanswered questions. The authors sought to develop a set of guidelines for the use of ketamine in acute pain management, and in particular, to formulate indications, contraindications, and guidance for the use of the drug as an opioid adjunctive therapy, in patient-controlled analgesia (PCA), and in nonparenteral formulations, and to determine optimal subanesthetic dosage ranges.
The group concluded that ketamine infusions were indicated and should be considered for painful surgeries and for surgeries in which the patient was opioid tolerant or opioid dependent. In addition, ketamine might be used as an adjunct medication in individuals misusing opioid medications, in those who are experiencing sickle cell crises, or those have obstructive sleep apnea, to limit opioid exposure.
It was recommended that intravenous (IV) boluses of ≤0.35 mg/kg ketamine be administered, with infusion rates ≤1.0 mg/kg/hr. The group recognized this would not likely apply to all patients, with some people requiring higher or lower dosages, depending on pharmacodynamics, pharmacokinetics, prior usage, and the need to balance analgesic efficacy with safety concerns. They also found moderate evidence supporting these IV dosage levels for use as opioid adjunctive therapy in the perioperative setting.
Practitioners should avoid using ketamine in certain situations, including in women who are pregnant or those who are actively psychotic, or in patients with poorly controlled cardiovascular disease. Ketamine should not be administered to individuals with severe hepatic dysfunction and should be given with caution and monitoring to those with moderate illness. Patients with increased intracranial or intraocular pressure should not receive ketamine infusions.
Nonparenteral formulations of ketamine were determined to have selective benefits in certain scenarios and populations. Intranasal ketamine may result in analgesia but also amnesia and sedation during procedures, particularly in children or those with problematic IV access. Although there is less certainty concerning the efficacy of oral ketamine, it might prove useful in some patients with acute pain, at least in the short term.
Although evidence supporting the use of ketamine alone for patient-controlled analgesia is limited in terms of analgesic effectiveness for acute pain reduction, the investigators determined that more robust support exists for adding ketamine to an opioid-based patient-controlled analgesia regimen.
“In conclusion, despite its drawbacks, ketamine remains a powerful and inexpensive tool for practitioners who manage acute pain,” noted the guideline authors, who suggested that future studies examine various dosage ranges and levels of opioid tolerance, in addition to less well-studied conditions such as pancreatitis, sickle cell disease, and neuropathic pain syndromes.
Schwenk ES, Viscusi ER, Buvanendran A, et al. 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;43(5):456-466.