Common Anesthesia Medications: Adult and Pediatric Dosing and Side Effects
For procedural sedation in both adults and children, ketamine and propofol are the most evidence-supported agents, with ketamine being particularly safe and effective in pediatrics when dosed appropriately by age. 1, 2
Ketamine
Pediatric Dosing
- Intramuscular (IM): Initial dose 4 mg/kg, with repeat dose of 2-4 mg/kg at 5-10 minutes if needed 1
- Intravenous (IV):
- Single bolus: 2.125 mg/kg (age 2 years), 2 mg/kg (age 6 years), 1.75 mg/kg (age 12 years) 3
- Preferred technique for intermittent pain: Smaller initial bolus (1-1.5 mg/kg) with half-dose top-up at 8 minutes—achieves same sedation with faster recovery 3
- Preferred technique for continuous pain: 0.35 mg/kg bolus (age 2 years), 0.3 mg/kg (age 6 years), 0.275 mg/kg (age 12 years), followed by infusion of 3.5,3, and 2.75 mg/kg/hour respectively for 15 minutes 3
Adult Dosing
- IV: 1.5 mg/kg single bolus or 0.25 mg/kg bolus followed by 2.5 mg/kg/hour infusion 3
- When combined with midazolam: 2 mg/kg IV ketamine after 0.07 mg/kg IV midazolam 2
Side Effects (Both Populations)
- Respiratory: Airway complications in 1.4% (no intubations required), transient apnea with rapid IV infusion, laryngospasm (rare) 1
- Gastrointestinal: Emesis 6.7% (increases with age, OR 1.25/year; no aspiration events reported) 1
- Neuropsychiatric:
- Cardiovascular: Generally stable hemodynamics; propofol-ketamine combination maintains heart rate at 92.2 ± 16.8 bpm 4
Key Clinical Point: Ketamine has Level A evidence for safe use in pediatric procedural sedation 2. Recovery time with single IM dose is median 110 minutes; IV techniques with infusion allow recovery to drowsy state in 20 minutes 1, 3.
Propofol
Dosing
- Pediatric and Adult: Titrate to clinical effect; no specific mg/kg doses recommended in guidelines due to high variability 2
- Context-sensitive half-life is short beyond first year of life, allowing for more precise age-adapted dosing 5
Side Effects
- Respiratory: Desaturation most common; transient apnea requiring bag-mask ventilation (rare) 2
- Cardiovascular: Hypotension (monitor carefully) 2
- Other: Pain on injection 2
Key Clinical Point: Propofol has Level B evidence for safe use in procedural sedation when titrated to effect 2. Consider total intravenous anesthesia (TIVA) with propofol as standard for preventing emergence agitation in pediatrics 5.
Etomidate
Dosing
- Standard procedural sedation doses used (specific mg/kg not provided in guidelines)
Side Effects
- Respiratory: Desaturation below 90-94% in 5-8% (all recovered uneventfully); transient apnea requiring bag-mask ventilation (rare) 2
- Musculoskeletal: Myoclonus 0-21% (usually <1 minute, benign, not epileptogenic but can cause brief desaturation) 2
- Other: Pain with injection 2
Key Clinical Point: Etomidate has Level C evidence for safe use in procedural sedation 2. Myoclonus can be dramatic and resemble seizure activity but is benign.
Fentanyl
Dosing
Side Effects
- Respiratory: Respiratory compromise 0.7% 2
- Cardiovascular: Hypotension 0.4% 2
- No sequelae associated with comorbid factors (alcohol, head trauma) 2
Key Clinical Point: When combined with midazolam, this combination has Level B evidence for effectiveness in procedural sedation 2. Naloxone should be immediately available.
Midazolam
Dosing
- Adult: 0.07 mg/kg IV when used with ketamine 2
- Pediatric: Used as anxiolytic premedication and in combination regimens 5
Side Effects
- Respiratory depression when combined with opioids (titration essential) 2
- Excellent anxiolytic profile 5
Key Clinical Point: Midazolam is superior as an anxiolytic compared to dexmedetomidine, though dexmedetomidine is better for postoperative sedation 5.
Dexmedetomidine
Dosing
- Used as adjunct to prolong peripheral nerve blocks in children 6
- Specific procedural sedation doses not provided in guidelines
Side Effects
- Cardiovascular: Hypotension (requires careful monitoring) 4
- Fewer overall complications compared to other regimens 4
- Superior sedative properties and particularly beneficial postoperatively 5
Local Anesthetics
Pediatric Regional Anesthesia Dosing
- Spinal bupivacaine: 1 mg/kg (newborns/infants), 0.5 mg/kg (>1 year) 6
- Spinal tetracaine 0.5%: 0.07-0.13 mL/kg 6
- Peripheral nerve blocks (bupivacaine or ropivacaine): 0.5-1.5 mg/kg for upper extremity blocks 6
Maximum Doses (General Principles)
- Not evidence-based fixed numbers—must be block-specific and adjusted for: injection site, age, organ dysfunction, pregnancy 7
- Add epinephrine 2.5-5 mcg/mL when large doses used (if no contraindications) 7
- Reduce doses for: end-stage pregnancy, high age, uremia (increased uptake rate) 7
- Reduce doses for repeated/continuous administration in: renal, hepatic, cardiac disease (reduced clearance) 7
Side Effects
- Local Anesthetic Systemic Toxicity (LAST): Ranges from mild hypertension to refractory cardiac dysfunction, dysrhythmias, cardiac arrest 8
- Treatment: Intravenous lipid emulsion is life-saving in severe cases 8
Critical Dosing Principles
Age-dependent dosing is essential: Postmenstrual age (not postnatal age) is the appropriate maturation measure 9. Dosing generally increases with decreasing age for ketamine due to pharmacokinetic differences 3.
Common Pitfall: Using large single ketamine doses leads to deep sedation, possible adverse effects, and delayed recovery (70 minutes to drowsy state). Top-up or infusion techniques provide more even sedation and rapid recovery (20 minutes) 3.
Respiratory depression is the most concerning side effect across all agents, but careful preparation, titration, and monitoring prevent harmful sequelae 2.