Maintenance Dose Calculator
Calculate the maintenance dose required to maintain steady-state drug concentration based on drug clearance and pharmacokinetic parameters.
Patient & Drug Parameters
mg/L
Desired steady-state concentration
hours
Time between doses (e.g., 8 for TID)
%
Dose Per Interval
480.0 mg
Every 8 hours (3 times daily)
⏱️Dose Rate
60.00 mg/hr
📅Daily Dose
1440.0 mg
⚖️Dose Per kg
6.86 mg/kg
📊Daily Per kg
20.57 mg/kg/day
Formula
Dose = (Cl × Cpss × tau) / (F × S)
Where tau = dosing interval, Cl = clearance, Cpss = target concentration
Dosing Summary
Give 480.0 mg every 8 hours
Total daily dose: 1440.0 mg/day
Clearance used: 6.00 L/hr
Pharmacokinetic Principles
Steady State
- Reached after 4-5 half-lives
- Input rate = Output rate
- Drug accumulates until equilibrium
- Loading dose can achieve Cpss immediately
Dosing Intervals
- QD (once daily): 24 hours
- BID (twice daily): 12 hours
- TID (three times daily): 8 hours
- QID (four times daily): 6 hours