Maintenance Dose Calculator
Calculate maintenance doses to maintain therapeutic concentrations
Steady State
Maintenance Dose Calculation
Target Concentration
Steady-state average concentration
Therapeutic Ranges
Digoxin: 0.8-2.0 mcg/L
Vancomycin: 10-20 mg/L (trough)
Phenytoin: 10-20 mg/L
Vancomycin: 10-20 mg/L (trough)
Phenytoin: 10-20 mg/L
Clearance
Dosing Interval
Advanced Parameters
Maintenance Dose Formula
MD = (Cₛₛ × Cl × τ) ÷ F
Where:
• Cₛₛ = Target steady-state concentration
• Cl = Clearance
• τ = Dosing interval
• F = Bioavailability fraction
• Cₛₛ = Target steady-state concentration
• Cl = Clearance
• τ = Dosing interval
• F = Bioavailability fraction
Example Drugs
Maintenance Dose
Dose per Interval
Enter Values
Dosing Strategy
Frequency:
Twice daily
Timing:
Consistent intervals recommended
Adjustments:
Based on therapeutic drug monitoring
Important Considerations
- • Adjust for renal/hepatic impairment
- • Consider drug interactions
- • Monitor for efficacy and toxicity
- • Loading dose may be needed initially
- • Individualize based on patient factors
Maintenance Dosing Principles
Steady State Concept
• Rate in = Rate out at steady state
• Achieved after 4-5 half-lives
• Independent of loading dose
• Maintenance dose replaces eliminated drug
Accumulation
• R = 1/(1 - e^(-k×τ))
• Depends on dosing interval relative to half-life
• Shorter interval = more accumulation
• Important for toxicity prediction
Clinical Application
• Start with estimated dose
• Monitor concentrations at steady state
• Adjust based on therapeutic response
• Consider individual variability