Ketamine - (Sub-dissociative dosing)   (PDF)

Ketamine is NMDA receptor antagonist and potent analgesic with a mechanism of action that is different from opioids. Ketamine has a long history of use in the ED – particularly in the pediatric context for procedural sedation.

However, there is now preliminary data on the use of "sub-dissociative" ketamine dosing that suggests efficacy that is similar to opioids. Ketamine may provide benefit in patients who have pain that is refractory to standard narcotic pain medications or in patients with relative contraindications to standard therapies. Moreover, the evidence suggests a side effect profile that is similar to opioids in appropriately selected patient populations.

To be clear, the data overall is early and have not been proven any significant benefit over opioids. In addition, ketamine does not provide long-term pain control, and cannot be prescribed on discharge. And finally for procedural sedation, the use of standard dissociative dosing for adequate analgesia is strongly recommended.

ED Summary

Use of sub-dissociative ketamine must be carefully considered for the appropriate patient (see contraindications below) in the right clinical context.

Dosing and administration:

• 0.3 mg/kg IV over 3-5 min (range 0.2-0.3 mg/kg)
• Must be approved by attending physician and administered by prescriber (RN may not administer)
• May be repeated x 1 dose in 60 minutes (Maximum of 2 doses)
• No dilution required

Monitoring:

• BP, HR, RR, O2 sat, pain score prior to administration, 15 min after administration, and 60 min after administration
• Patients who receive ketamine in the ED cannot drive home

Absolute Contraindications:

• History of schizophrenia (even if well controlled)
• Pregnancy/Breastfeeding

Relative Contraindications:

• Altered Mental status
• Severe hepatic impairment
• Active pulmonary infection or disease, including URI or asthma (higher risk of laryngospasm)
• Known or suspected cardiac disease (history of MI, stents, bypass, CHF)
• History of airway instability, tracheal stenosis or tracheal surgery (presumed higher risk of airway compromise)
• Unstable vital signs (SBP <90mmHg or >180mmHg, HR<50 or >150 bpm, RR <10 or >30)
• Acute head injury (elevated ICP)
• CNS masses or hydrocephalus
• Glaucoma or acute globe injury (increased intraocular pressure)
• Major procedures stimulating the oropharynx (endoscopy)

Adverse Effects

• Dizziness
• Light-headedness
• Disorientation/confusion
• Mood Changes
• Nausea
• Cardiac arrhythmias

References:

• Motov S, et al. Intravenous subdissociative-dose ketamine versus morphine for analgesia in the emergency department: a randomized controlled trial. Ann Emerg Med. 2015;66:222-229
• Beaudoin FL, et at. Low-dose ketamine improves pain relief in patients receiving intravenous opioids for acute pain in the emergency department: results of a randomized, double-blind, clinical trial. Academic Emergency Medicine 2014;21:1194-1202.
• Bowers KJ et al. Ketamine as an adjunct to opiates for acute pain in the emergency department. Abstract American College of Emergency Physicians 2015 Research Forum October 26-27, 2015 Boston, MA.

Authors:

• Mustapha Saheed
• Melinda Ortmann
• Umbreen Murtaza
• Karolina DeAugustinis