What is the recommended dose of ketamine (intravenous anesthetic) for a patient?

Recommended Ketamine Dosing for Intravenous Anesthesia

For intravenous anesthesia, ketamine should be administered at 1.5-2 mg/kg IV for most adult patients, with continuous monitoring of vital signs and airway status. 1, 2

Standard Dosing Recommendations

Intravenous Administration

• The FDA-approved intravenous dose of ketamine for induction of anesthesia ranges from 1 mg/kg to 4.5 mg/kg, with 2 mg/kg being the average dose required to produce 5-10 minutes of surgical anesthesia 1
• Administer ketamine slowly over 60 seconds to prevent respiratory depression and enhanced vasopressor response 1
• For procedural sedation, 1.5-2 mg/kg IV is more effective than 1.0 mg/kg, with only 5.5% of patients requiring additional doses at the higher dose compared to 54% with the lower dose 2, 3

Maintenance of Anesthesia

• For maintenance of anesthesia, repeat increments of one-half to the full induction dose as needed 1
• Alternatively, a continuous infusion of 0.1-0.5 mg/minute can maintain general anesthesia in adult patients initially induced with ketamine 1
• For pediatric patients receiving ketamine as a co-analgesic drug, a continuous infusion of 0.1-0.2 mg/kg/h (maximum: 0.4 mg/kg/h) may be used 3

Breakthrough Pain Management

• For breakthrough pain in post-anesthesia care units, ketamine can be administered at 0.5 mg/kg, titrated to effect 3
• When using S-ketamine (the S-enantiomer of ketamine), consider a reduced dose of 0.25-0.5 mg/kg 3

Special Considerations

Administration Safety

• Ketamine should only be administered by or under the direction of physicians experienced in administering general anesthetics and maintaining a patent airway 1
• Emergency airway equipment must be immediately available during ketamine administration 1
• The 100 mg/mL concentration must be diluted before intravenous administration 1

Recovery Time

• Average recovery time after IV ketamine administration is approximately 84 minutes (range: 22-215 minutes) 4, 2
• For pediatric patients, the median recovery time is 103 minutes (interquartile range: 76-146 minutes) 4
• Patients should be continuously monitored during the recovery period with particular attention to vital signs 4, 2

Common Side Effects

• Mild recovery agitation occurs in approximately 17.6% of patients, with moderate-to-severe agitation in about 1.6% 4, 2
• Emesis without aspiration is reported in 6.7% of cases 4, 2
• Consider administering an antisialagogue prior to induction to reduce salivation 1
• Consider adding a benzodiazepine to prevent neuropsychological manifestations during emergence from anesthesia 1

Contraindications and Cautions

• Avoid rapid administration as it may result in respiratory depression 1
• Use with caution in patients with ischemic heart disease, cerebrovascular disease, or hypertension due to ketamine's sympathomimetic effects 2
• In individuals with a history of chronic ketamine use, monitor for genitourinary pain 1

Pediatric Dosing

• For pediatric procedural sedation, IV ketamine at 1.5 mg/kg is recommended 2, 5
• For intramuscular administration in children, 4 mg/kg is recommended, with repeat doses of 2-4 mg/kg allowed after 5-10 minutes if needed 2
• Recovery agitation is associated with higher ASA status (>I) and decreasing age 2

By following these evidence-based dosing guidelines and monitoring protocols, ketamine can be safely and effectively administered for anesthesia while minimizing adverse effects and optimizing patient outcomes.