Dose :  The administered dose, mg

F :  The drug bioavailability, unitless

Dosing interval :  The time between doses, hours

k_a :  The first order absorption rate constant, hour ^-1

Vd :  The volume of distribution, liters

k (CL_T/Vd) :  The first order elimination rate constant, hour ^-1

E :  is the intensity of the effect

E_max :  is the maximum effect

n :  is the sigmoidicity factor. (Unitless).

EC₅₀ :  is the drug conc when the effect is 50% of the maximum effect (amount/volume)

C :  is the drug concentration at the site of action, the plasma (amount/volume)