Ketamine Dosing Calculation
Draw up 0.56 mL (or approximately 0.6 mL) into each syringe for two separate doses of 28 mg each, given 15 minutes apart.
Calculation Breakdown
Your vial concentration is 100 mg/mL 1. To deliver 56 mg total ketamine split into two doses:
- Total dose needed: 56 mg
- Dose per syringe: 56 mg ÷ 2 = 28 mg per dose
- Volume calculation: 28 mg ÷ 100 mg/mL = 0.28 mL per syringe
Wait—I need to clarify your dosing strategy here, as the question is ambiguous about whether you want:
Option A: Two 28 mg doses (56 mg total)
- Draw 0.28 mL into each of two syringes
- Give first dose now, second dose at 15 minutes
- Total delivered: 56 mg
Option B: Two 56 mg doses (112 mg total)
- Draw 0.56 mL into each of two syringes
- Give first dose now, second dose at 15 minutes
- Total delivered: 112 mg
Clinical Context for Ketamine Dosing
The appropriate interpretation depends on your clinical indication:
For IV procedural sedation 2, 3:
- Initial bolus: 1.5-2 mg/kg IV
- Repeat dosing at 5-10 minutes: typically half the initial dose
- A "top-up" technique with smaller initial dose followed by half-dose at 8 minutes achieves better sedation with earlier recovery 3
For IM procedural sedation 2, 4:
- Initial dose: 4 mg/kg IM
- Repeat allowed in 5-10 minutes: 2-4 mg/kg IM
- Optimal IM dosing is 4-5 mg/kg for adequate sedation in 93-100% of children 4
Critical Safety Considerations
- Monitor continuously: Oxygen saturation, respiratory status, and cardiovascular parameters 2
- Airway management: Be prepared for laryngospasm (1.4% incidence) and respiratory depression 2
- Recovery time: Median 82-110 minutes from last dose to discharge 2
- Adverse effects: Emesis (6.7%), recovery agitation (17.6% mild, 1.6% moderate-severe) 2
Most likely scenario: If you're splitting a 56 mg dose, you want 0.28 mL per syringe for two 28 mg doses given 15 minutes apart.