What is the recommended initial dose of intravenous (IV) ketamine for procedural sedation?

IV Ketamine Dosing for Procedural Sedation

The recommended initial dose of intravenous (IV) ketamine for procedural sedation is 1-1.5 mg/kg. 1, 2, 3

Dosing Recommendations by Age Group

Pediatric Patients

• Initial dose: 1-1.5 mg/kg IV 1, 2
• Administered slowly over 60 seconds to prevent respiratory depression 3
• Additional doses of 0.25-0.5 mg/kg may be given as needed 4
• Studies show that 88% of pediatric patients can be successfully sedated with initial doses of 1 mg/kg or less 4

Adult Patients

• Initial dose: 1-1.5 mg/kg IV 3
• FDA labeling indicates a range of 1-4.5 mg/kg IV, with 2 mg/kg being the average dose for 5-10 minutes of surgical anesthesia 3
• For older adults (>50 years), consider using the lower end of the dosing range to minimize cardiovascular effects 5

Comparative Efficacy of Different Dosing Regimens

Research has compared the efficacy of different initial ketamine doses:

• 1.0 mg/kg vs 1.5 mg/kg: Patients receiving 1.5 mg/kg required fewer total doses (median 1 vs 2 doses) and had a lower overall mg/kg dosage (1.60 vs 1.71 mg/kg) 6
• 1.5 mg/kg regimen: Only 7.6% of patients required a third dose to complete sedation 6
• 1.0 mg/kg regimen: 18.5% of patients required a third dose to complete sedation 6

Administration Technique

• Administer IV ketamine slowly over 60 seconds 3
• Rapid administration may result in respiratory depression and enhanced vasopressor response 3
• For continuous sedation, ketamine can be administered via slow microdrip infusion at 0.1-0.5 mg/minute 3

Safety Considerations and Monitoring

• Continuous monitoring of vital signs is essential 2, 3
• Emergency airway equipment must be immediately available 3
• Consider administering an antisialagogue (e.g., atropine, glycopyrrolate) prior to ketamine to reduce secretions 3
• In adults >50 years, ECG monitoring may be warranted due to potential cardiovascular effects (9.7% showed new ECG changes in one study) 5

Common Adverse Effects and Management

• Emergence reactions: Consider adding midazolam (0.05 mg/kg IV) to reduce incidence 2
• Emesis: More common with increasing age 1
• Recovery agitation: Associated with higher ASA status and decreasing age 1
• Airway complications: Rare (1.4%) and typically without need for intubation 1

Recovery Time

• Median recovery time with IV ketamine: approximately 103 minutes (range 76-146 minutes) 1
• When ketamine is combined with propofol, recovery times may be shortened 7

Pitfalls to Avoid

1. Rapid administration: Always administer IV ketamine slowly over 60 seconds to prevent respiratory depression and enhanced vasopressor response 3

2. Inadequate monitoring: Continuous monitoring of vital signs is essential, with emergency airway equipment immediately available 2, 3

3. Underdosing in pediatric patients: While lower doses (0.5-1.0 mg/kg) may be effective in some cases 4, starting with 1.5 mg/kg results in fewer total doses needed and more reliable sedation 6

4. Failure to consider adjuncts: Consider adding midazolam to reduce emergence reactions, particularly in patients >10 years 1

5. Using concentrated ketamine (100 mg/mL) without dilution: This concentration must be diluted before IV administration 3

In summary, IV ketamine at 1-1.5 mg/kg provides effective procedural sedation with a favorable safety profile when administered properly and with appropriate monitoring.