What is the recommended IV (intravenous) induction dose of ketamine?

Recommended IV Induction Dose of Ketamine

The recommended intravenous (IV) induction dose of ketamine for general anesthesia is 1-2 mg/kg administered slowly over 60 seconds. 1

Adult Dosing

General Anesthesia Induction

• IV ketamine should be administered at 1-4.5 mg/kg for induction of anesthesia, with the average effective dose being 2 mg/kg to produce 5-10 minutes of surgical anesthesia 1
• Administration should be slow (over a period of 60 seconds) to prevent respiratory depression and enhanced vasopressor response 1
• Alternatively, the induction dose may be administered as an IV infusion at a rate of 0.5 mg/kg/min 1

Procedural Sedation

• For procedural sedation, lower doses of 1-1.5 mg/kg IV are often effective 2
• Studies have shown that doses as low as 0.5-1.0 mg/kg may provide adequate sedation in many pediatric patients 3

Special Populations

High-Risk Patients (ASA III-IV)

• For ASA class III and IV premedicated patients, the ED50 (effective dose in 50% of patients) for abolition of response to painful stimulation is 1.3 mg/kg 4
• The ED95 (effective dose in 95% of patients) for these high-risk patients is 4.3 mg/kg 4

Pediatric Patients

• In pediatric patients, IV ketamine at 1.5 mg/kg has been shown to be more effective than 1.0 mg/kg for procedural sedation 2
• For orthopedic procedures in children, 2 mg/kg IV provides adequate sedation with an average onset time of 96 seconds 2, 5

Perioperative Pain Management

• For perioperative pain management, ketamine is recommended at a maximum dose of 0.5 mg/kg/h after anesthesia induction, followed by continuous infusion at 0.125-0.25 mg/kg/h 2
• This regimen is particularly beneficial for:
  1. Surgeries with high risk of acute or chronic postoperative pain
  2. Patients with vulnerability to pain, especially those taking long-term opioids or with opioid addiction 2

Administration Considerations

• Ketamine should be administered by or under the direction of physicians experienced in general anesthesia, airway management, and ventilation 1
• Continuous monitoring of vital signs is essential, including ECG, pulse oximetry, and regular blood pressure measurements 2
• Emergency airway equipment must be immediately available 1
• An antisialagogue should be administered prior to induction due to potential for increased salivation 1

Cautions and Contraindications

• Rapid administration may result in respiratory depression and enhanced vasopressor response 1
• Ketamine causes significant increases in blood pressure and heart rate, which may be problematic in certain patients 4
• Consider benzodiazepine co-administration to prevent neuropsychological manifestations during emergence from anesthesia 1

Follow-up Dosing

• For maintenance of anesthesia, repeat increments of one-half to the full induction dose as needed 1
• Alternatively, ketamine can be administered by slow microdrip infusion at 0.1-0.5 mg/minute to maintain general anesthesia in adults 1

The evidence strongly supports that while the FDA-approved range for IV ketamine induction is 1-4.5 mg/kg, most clinical practice has settled on 1-2 mg/kg as the optimal balance between efficacy and safety for most adult patients requiring general anesthesia.