IM Ketamine Dosing
For intramuscular ketamine administration, use 6.5-13 mg/kg in adults and children, with 9-13 mg/kg producing surgical anesthesia within 3-4 minutes and lasting 12-25 minutes. 1
Standard IM Dosing by Indication
Induction of Anesthesia
- Initial dose range: 6.5-13 mg/kg IM 1
- Optimal dose: 9-13 mg/kg produces surgical anesthesia within 3-4 minutes 1
- Duration: Anesthetic effect typically lasts 12-25 minutes 1
Procedural Sedation (Pediatrics)
- Recommended dose: 4-5 mg/kg IM produces adequate sedation in 93-100% of children 2
- Lower doses (<4 mg/kg) result in inadequate sedation in up to 9% of cases 2
- Higher doses (>5 mg/kg) provide no additional benefit in time to discharge or adverse effects 2
- Bioavailability: IM ketamine has 41% bioavailability in children 3
Analgesia (Emergency/Trauma)
- Low-dose analgesia: 0.5 mg/kg IM provides good but short-lasting analgesia with minimal side effects 4
- Higher analgesia: 1.0 mg/kg IM provides more intense and longer-lasting analgesia but causes impaired consciousness and disorientation 4
Rapid Sequence Induction (Pediatrics)
- IV/IO dose: 0.2-0.4 mg/kg (maximum 20 mg) 5
- Note: This is IV dosing; IM would require higher doses per standard conversion
Special Populations & Dose Modifications
Elderly Patients
- No specific IM dose reduction provided in guidelines
- Exercise caution due to potential cardiovascular effects 6
- In critically ill elderly patients, ketamine may paradoxically decrease cardiac output and contractility 6
Severe Hepatic Impairment
- Ketamine appears safe in chronic liver disease 7
- No dose adjustment specifically recommended in available evidence
- However, monitor liver function with chronic use 8
- Recent data shows disproportionately higher reporting of hepatic cytolysis with ketamine 8
Cardiovascular Disease
- Use with extreme caution or avoid 9
- Ketamine increases heart rate, blood pressure, and cardiac output via sympathetic stimulation 9
- Contraindicated in ischemic heart disease, cerebrovascular disease, or uncontrolled hypertension 9
- In critically ill patients, ketamine may cause paradoxical cardiovascular depression 6
Clinical Pearls & Safety Considerations
Administration Technique
- Antisialagogue recommended prior to induction due to increased salivation 1
- Benzodiazepine co-administration (e.g., midazolam) reduces emergence reactions in adults 10, 9
- Emergence reactions occur in 10-30% of adults without benzodiazepine prophylaxis 9
Monitoring Requirements
- Continuous vital sign monitoring mandatory 1
- Emergency airway equipment must be immediately available 1
- Active laryngeal-pharyngeal reflexes provide some airway protection, but aspiration can still occur 1
When to Choose IM Over IV
- Combative patients where IV access is difficult 11
- Patients with history of IV drug abuse 11
- Pediatric patients requiring procedural sedation without IV access 10
- IM route allows sedation first, then establish vascular access 11
Common Pitfalls
- Avoid rapid IV administration of concentrated solutions (100 mg/mL) without dilution 1
- Do not assume adequate sedation from purposeless/tonic-clonic movements—these are normal and don't indicate need for additional doses 1
- Prolonged postoperative ketamine increases hallucination risk without significant analgesic benefit 12
- Genitourinary symptoms may develop with chronic off-label use; consider cessation if persistent 1