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IBW / ABW
Calculate IBW for drug dosing (aminoglycosides, vancomycin, chemotherapy) and ventilator tidal volume. Use ABW for obese patients when indicated.
Indication
- Calculate IBW for drug dosing (aminoglycosides, vancomycin, chemotherapy) and ventilator tidal volume. Use ABW for obese patients when indicated.
Criteria
- id: height; label: Height; type: number; placeholder: enter value
- id: height_unit; label: Height Unit; type: options; defaultValue: cm; options: value: cm; label: cm; value: in; label: inches
- id: sex; label: Sex; type: options; options: value: male; label: Male; value: female; label: Female
- id: weight; label: Actual Body Weight (kg); type: number; placeholder: e.g. 90
Clinical pearls
- Never use actual weight for aminoglycoside dosing in obese patients — risk of toxicity; use IBW or ABW
- Tidal volume for mechanical ventilation is always based on IBW, not actual weight (target 6–8 mL/kg)
- ABW is used when actual weight is more than 20–30% above IBW
- Vancomycin and enoxaparin are dosed on actual body weight
Source and review
- Devine BJ. Drug Intell Clin Pharm 1974; ARDSnet protocol. Last reviewed: 2025-01-01