What is the appropriate dose of intramuscular (IM) ketamine for a pediatric patient?

Appropriate IM Ketamine Dose for Pediatric Patients

For pediatric procedural sedation, administer 4 mg/kg intramuscularly, with the option to repeat at 2-4 mg/kg after 5-10 minutes if initial sedation is inadequate. 1

Standard Dosing Protocol

• The recommended initial IM dose is 4 mg/kg, which has been validated in over 1,022 pediatric cases and produces adequate sedation in 98% of patients 1, 2
• If sedation remains inadequate after 5-10 minutes, administer a repeat dose of 2-4 mg/kg IM 1
• Onset of action occurs within 3-5 minutes after IM administration, significantly faster than alternative sedatives 3, 2

Expected Clinical Course

• Median time from injection to discharge is 110 minutes for a single IM dose, though this includes observation time beyond pharmacologic recovery 1, 3
• The procedure can typically begin within 5 minutes of administration in 83% of patients 1
• Recovery behavior is quiet in approximately 80% of patients 3

Adjunctive Medication Considerations

• Consider co-administering atropine 0.01 mg/kg IM (minimum 0.1 mg, maximum 0.5 mg) to reduce hypersalivation, which results in faster onset (3 minutes vs 18 minutes) and shorter discharge times 1, 3
• For patients over 10 years old, adding midazolam may reduce recovery agitation from 35.7% to 5.7%, though this requires IV access 3

Safety Profile and Adverse Events

• Transient airway complications occur in only 1.4% of cases, including airway malalignment, laryngospasm, apnea, or respiratory depression—all managed without intubation or sequelae 1, 2
• Emesis without aspiration occurs in 6.7% of cases and is more common with increasing age 1, 2
• Mild recovery agitation occurs in 17.6% of patients, with moderate-to-severe agitation in only 1.6% 1, 2
• Recovery agitation is associated with younger age and higher ASA status (>I) 1

Critical Monitoring Requirements

• Continuous pulse oximetry, heart rate, and blood pressure monitoring is mandatory throughout the procedure and recovery period 1, 3
• Have oxygen and airway management equipment immediately available, including bag-valve-mask ventilation capability 1, 3
• A second staff member trained in airway management must be present solely for monitoring, separate from the proceduralist 1

Absolute Contraindications

• Avoid IM ketamine in patients with: active psychosis, uncontrolled hypertension, ischemic heart disease, cerebrovascular disease, elevated intracranial pressure, elevated intraocular pressure, or severe hepatic dysfunction 3, 4

Common Pitfalls to Avoid

• Do not underdose—the 4 mg/kg dose is critical for achieving adequate sedation; lower doses result in significantly higher failure rates requiring repeat dosing 1, 2
• Do not discharge prematurely—patients must return to baseline mental status with stable vital signs and adequate airway reflexes before discharge 3
• Laryngospasm is most often associated with concomitant upper respiratory infection; screen for active URI before administration 1