Ketamine in Pain Management

Sub-Dissociative Dose Ketamine (SDK) in Pain Management

1. Pharmacology & Mechanism of Action

Ketamine is an N-methyl-D-aspartate (NMDA) receptor antagonist. In sub-dissociative analgesic doses (0.1–0.3 mg/kg IV), ketamine blocks NMDA-mediated central sensitization, wind-up phenomenon, and hyperalgesia without inducing general anesthesia or procedural dissociation.

2. Dosing Spectrum & Clinical Administration

Dosing Category	Intravenous Dose Range	Primary Clinical Purpose & Effects
Sub-Dissociative Analgesic (SDK)	0.1 – 0.3 mg/kg IV bolus / infusion	Analgesia; opioid-sparing; preserves airway reflexes & hemodynamics
Dissociative Sedation	1.0 – 2.0 mg/kg IV (4-5 mg/kg IM)	Procedural sedation; complete sensory dissociation
Continuous Infusion	0.15 – 0.2 mg/kg/hr IV	Refractory acute pain; perioperative opioid reduction

3. Clinical Indications & Safety Profile

Sub-dissociative ketamine is indicated as a single agent or opioid adjunct in severe acute pain, traumatic injuries, acute sickle cell crisis, opioid-tolerant patients, and renal/hepatic failure where standard non-opioid options are contraindicated.

Administration Best Practice: Administering SDK as a 15-minute short infusion (diluted in 100 mL 0.9% saline) significantly reduces transient psychomimetic side effects (feeling of unreality, dizziness) compared to rapid IV push.
Hemodynamic & Airway Safety: Unlike opioids or sedatives, SDK does not cause respiratory depression, hypoxemia, or hypotension, making it ideal for hemodynamically unstable trauma patients.

CLINICAL GUIDELINE SUMMARY: American College of Emergency Physicians (ACEP) Policy Resource Statement
ACEP guidelines state that sub-dissociative dose ketamine (0.1–0.3 mg/kg) is safe and effective for acute pain management in the ED, providing analgesia functionally equivalent to morphine while reducing overall opioid requirements without causing significant respiratory depression or emergence reactions.

References

ASRA/AAPM Consensus Guidelines: Schwenk ES, 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.

Related Posts