What is the recommended dosing for ketamine (Ketamine hydrochloride)?

Ketamine Dosing Recommendations

For procedural sedation and analgesia, ketamine should be administered at 1.5-2 mg/kg IV or 4 mg/kg IM, with continuous monitoring of vital signs and airway status. 1, 2

Intravenous Administration

• Initial IV dose ranges from 1-4.5 mg/kg, with 2 mg/kg being the average dose required to produce 5-10 minutes of surgical anesthesia 3
• Administer IV ketamine slowly over 60 seconds to prevent respiratory depression and enhanced vasopressor response 3
• 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 compared to 54% with the lower dose 1, 2
• For maintenance of anesthesia, ketamine can be administered via slow microdrip infusion at 0.1-0.5 mg/minute 3
• For pain management in critically ill adults, low-dose ketamine (0.5 mg/kg IVP followed by 1-2 μg/kg/min infusion) is recommended as an adjunct to opioid therapy 4

Intramuscular Administration

• Initial IM dose ranges from 6.5-13 mg/kg, with 9-13 mg/kg typically producing surgical anesthesia within 3-4 minutes 3
• For pediatric procedural sedation, 4 mg/kg IM is recommended, with repeat doses of 2-4 mg/kg allowed after 5-10 minutes if needed 4
• IM administration in combination with 0.01 mg/kg atropine results in faster onset of action (3 minutes vs. 18 minutes) and shorter time to discharge compared to other sedatives 2

Onset and Duration of Action

• IV ketamine has a rapid onset of action (30-96 seconds), allowing for quick procedural intervention 1
• IM ketamine typically produces effects within 3-4 minutes, with anesthetic effect lasting 12-25 minutes 3
• Average recovery time after IV ketamine administration is approximately 84 minutes (range: 22-215 minutes) 1, 5
• For patients receiving a single dose of IM ketamine, the median time from administration to discharge is 110 minutes 5

Monitoring and Safety Considerations

• Continuous monitoring of vital signs, including oxygen saturation, heart rate, and blood pressure, is required during ketamine administration 1, 2
• Patients should maintain oxygen saturation >93% on room air during the procedure 1, 5
• Consider administering an antisialagogue prior to induction of anesthesia due to potential for salivation 3
• Consider adding midazolam (0.05 mg/kg) to reduce the risk of emergence reactions, particularly in older children 1, 5

Common Side Effects

• Mild recovery agitation occurs in approximately 17.6% of patients, with moderate-to-severe agitation in about 1.6% 4
• Emesis without aspiration is reported in 6.7% of cases 4
• Other side effects include nausea (4-5%), ataxia (7-8%), and dysphoria (1%) 1, 2
• Emergence reactions (floating sensations, vivid dreams, hallucinations, and delirium) have been reported in 10-30% of adults 4

Special Considerations

• Ketamine causes a dose-dependent increase in heart rate, blood pressure, and cardiac output through stimulation of the sympathetic nervous system 4
• Use should be avoided in patients with ischemic heart disease, cerebrovascular disease, or hypertension 4
• New onset ischemia on ECG has been observed in 9.7% of adults over 50 years receiving ketamine for procedural sedation, though this did not impact patient disposition 6
• For dilution of the 100 mg/mL concentration, mix with an equal volume of either Sterile Water for injection, 0.9% Sodium Chloride Injection, or 5% Dextrose in Water before IV administration 3

Pediatric Considerations

• Ketamine is widely used and well-studied for pediatric procedural sedation 4
• Recovery agitation is associated with higher ASA status (>I) and decreasing age 4
• Emesis is associated with increasing age 4
• In a retrospective review of children, a combination of ketamine and midazolam resulted in less frequent inadequate sedation (3.1%) compared to other sedation regimens 4