Digoxin formulas

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The digoxin model is not hardcoded into the program. The parameters are found in the drug model database and are fully usereditable. You can tailor each drug model to fit your patient population, or you can create your own models. See the Edit drug models section of the help file for further information.
Initial dosing
1. Estimate Volume of Distribution (Jusko Equation)
Vd = 226 + [(298 x CrCl) / (29.1 + CrCl)] x (BSA / 1.73) where CrCl = normalized creatinine clearance(ml/min) BSA = Body surface area (square meters)
2. Calculate Loading Dose
LD = Vd x Cp/F where Vd = Volume of distribution (liters) Cp = target serum level (mcg/l) F = bioavailability factor: • IV push = 1 • capsules= 0.95 • elixir = 0.8 • tablets = 0.75
3. Estimate Clearance (KodaKimble)
Cl = [(A x CrCl) + B] x C where A = 0.88, for patient with Acute CHF, otherwise=1 B = 23, for patient with Acute CHF, otherwise=40 C = correction factor for interacting drugs: • Quinidine = 0.65 • Spironolactone = 0.75 • Verapamil = 0.7
4. Calculate Maintenance Dose
MD = (Cl x Cp x tau) / F where Cl = Clearance (liters/hour) Cp = target serum level (mcg/l) tau = dosing interval (hours) F = bioavailability factor
5. Estimate steadystate trough level
Cpss = (MD x F) / (Cl x tau) where MD = Maintenance dose (mcg) F = bioavailability factor Cl = Clearance (liters/hour) tau = dosing interval (hours)
Adjust maintenance dose
1. Estimate Volume of Distribution (Jusko Equation  see above)
2. Calculate digoxin clearance
Cl = [(MD x F) / Cp] / tau where MD = Maintenance dose (mcg) F = Bioavailability factor Cp = Steadystate serum digoxin concentration (mcg/l) tau = Dosing interval (hours)
3. Calculate Maintenance Dose
MD = (Cl x Cp x tau) / F where Cl = Digoxin clearance (l/hr) Cp = target serum level (mcg/l) tau = dosing interval (hours) F = bioavailability factor
4. Estimate steadystate trough level
Cpss = (MD x F) / (Kel x Vd x tau) where MD = Maintenance dose (mcg) F = bioavailability factor Kel = Elimination rate (1/hours) Vd = Volume of distribution (liters) tau = dosing interval (hours)
See also:
