The first consensus guidelines designed for managing I.V. ketamine infusions in patients with acute pain. Approved by the American Society of Regional Anesthesia and Pain Medicine (ASRA), the American Academy of Pain Medicine (AAPM), and the American Society of Anesthesiologists, this tool provided clinicians in acute care facilities with long sought-after direction for using ketamine to achieve safer and more effective pain control. The study was published in Regional Anesthesia and Acute Pain.
Opioids have been the gold standard for the treatment of both acute and chronic pain for a long period. Unfortunately, the opioid crisis that we are facing in this country has forced us to rethink how we utilize opioids.
With that being said, patients still experience pain for a variety of reasons. This means we must utilize a multimodal approach to treating pain. Issued alongside separate guidelines for the use of I.V. ketamine infusions in chronic pain management, these recommendations answered six key questions in response to a series of previously unaddressed concerns about using I.V. ketamine to treat acute pain.
They covered indications, contraindications, use of ketamine as an adjunct to opioid-based therapy, in patient-controlled analgesia (PCA), use of nonparenteral formulations, and evaluation of the optimal subanesthetic dosage range.
In higher doses, ketamine allegedly acts by reserving central sensitization and enhancing the descending modulatory pathway in the presence of pain. At lower doses used to manage acute pain, ketamine acts as an antagonist at the N-methyl-D-aspartate receptor, although it also acts at many other receptors, such as the µ-opioid, muscarinic, monoaminergic, gamma-aminobutyric receptors, and others.
Low-dose ketamine infusions were recommended for consideration in patients undergoing painful surgery and for opioid-dependent or opioid-tolerant patients undergoing surgery. Based on experience, the committee suggested considering ketamine in opioid-dependent or opioid-tolerant patients with acute or chronic sickle cell pain. For patients with sleep apnea, ketamine was noted as a potential adjunct to limit opioids.
Use Of Ketamine
The use of ketamine is limited by its relative contraindications, which include poorly controlled cardiovascular disease, some degrees of hepatic dysfunction, active psychosis, elevated intracranial or intraocular pressure, and pregnancy.
My advice to pharmacists would be to become familiar with ketamine because it is being utilized to treat a variety of conditions, and I expect that more research will be conducted to identify other conditions, optimal dosing, and perhaps even start being used in conditions [in] which it has not been used previously.