Ketamine Intramuscular Dosing Guidelines
For adults, the recommended intramuscular dose of ketamine is 6.5-13 mg/kg, with 9-13 mg/kg typically producing surgical anesthesia within 3-4 minutes and lasting 12-25 minutes. 1
Dosing by Population and Purpose
Adult Dosing
- Standard IM dose: 6.5-13 mg/kg 1
- Typical effective dose: 9-13 mg/kg for surgical anesthesia 1
- Onset of action: 3-4 minutes after IM injection 1
- Duration of effect: 12-25 minutes 1
Pediatric Dosing
- Initial IM dose: 3-4 mg/kg 2
- For procedural sedation: 4 mg/kg IM has been extensively studied and shown to be safe in over 1,000 pediatric cases 3
Special Situations
- For agitation/behavioral emergencies:
Administration Considerations
Safety Precautions
- Ketamine should be administered by or under direction of physicians experienced with general anesthetics 1
- Continuous monitoring of vital signs is essential 1
- Emergency airway equipment must be immediately available 1
- Consider administering an antisialagogue (e.g., atropine 0.02 mg/kg) prior to ketamine to reduce secretions 2
Monitoring Requirements
- Continuous pulse oximetry
- Heart rate and blood pressure monitoring every 5 minutes
- Close observation of respiratory status and level of consciousness
- Consider capnography for early detection of hypoventilation 2
Potential Complications
Common Side Effects
- Emergence reactions (can be reduced with benzodiazepine co-administration) 1
- Emesis (occurs in approximately 6.7% of pediatric patients) 3
- Tachycardia 2
Serious Adverse Events
- Respiratory depression (most common serious complication) 2
- Laryngospasm (occurs in 0.9-1.4% of emergency department cases) 2
- Airway complications requiring intervention (1.4% in large pediatric series) 3
Contraindications
- History of airway instability
- Active pulmonary infection or disease
- Increased intracranial pressure
- Psychosis 2
Clinical Pearls
- Bioavailability of IM ketamine in children is approximately 41% 6
- Recovery time: Median time from injection to discharge is approximately 110 minutes for children receiving a single dose 3
- When used for procedural sedation, ketamine has a high efficacy rate approaching 100% in clinical studies 2
- Purposeless and tonic-clonic movements may occur during ketamine anesthesia but do not indicate a need for additional doses 1
Ketamine's unique properties make it particularly valuable when vascular access is limited or impossible. The intramuscular route provides reliable sedation with a predictable onset, though requiring higher doses than intravenous administration due to first-pass metabolism and reduced bioavailability.