UMEM Educational Pearls

Category: Toxicology

Title: Ketamine for Severe Undifferentiated Acute Agitation

Keywords: Ketamine, Benzodiazepines (PubMed Search)

Posted: 4/7/2016 by Kathy Prybys, DO (Emailed: 4/8/2016) (Updated: 4/8/2016)
Click here to contact Kathy Prybys, DO


[CORRECTION]: Versed dose is 2-2.5 mg total not mg/kg

Patients with severe agitation present a unique challenge to the emergency department. Acute delirium is often due to psychostimulants such as cocaine, amphetamines, PCP, or synthetic cannabinoids, alcohol, or psychiatric illness. These patients require urgent evaluation necesssitating the use of physical and chemical restraints, not only for their own safety but also the hospital staff's. Fingerstick glucose, pulse oximetry, and vital signs must be expeditiously obtained. Severely agitated combative patients who are physically restrained are at high risk for morbidity from asphyxiation, hypermetabolic consequences (acidosis, hyperthermia, rhabdomyolysis), and death can occur.

Ketamine is phencyclidine derivative that causes dissociative state between the cortical and limbic systems which prevents the higher centers from preceiving visual, auditory, or painful stimuli. Ketamine has a wide safety profile and has been used worldwide for many years with few complications. It possesses ideal characteristics for rapid sedation of agitated patients:

  • Rapid onset of action 1-3 minutes
  • Preservation of airway reflexes
  • Lack of respiratory or cardiac depression or QT prolongation
  • Short half-life of 30-40 minutes
  • Safe in situations with minimal to no monitoring
  • Dose: Intravenous =1.5-2 mg/kg Intramuscular = 5-6 mg/kg (maximum 400 mg)

Experience with Ketamine in patients with excited delirium has shown good initial control of agitation however, patients often require additional medications for deeper or longer duration of sedation. Benzodiazepines are recommmended as second line agents particularly intravenous or intramuscular Midazolam 2-2.5 mg /kg.





Scheppke KA, Braghiroli J, Shalaby M, Chait R. Prehospital Use of IM Ketamine for Sedation of Violent and Agitated Patients. Western Journal of Emergency Medicine. 2014;15(7):736-741.

Isbister GK, Calver LA, et al. Ketamineas RescueTreatment for Difficult-to-Sedate Severe Acute Behavioral Disturbance in the Emergency Department. Ann Emerg Med 2016 Feb 10 [Epub ahead of print].