The elimination rate constant (alt: fractional elimination constant) ascertains the effect of a given clearance on the rate of drug removal from the body; it relates the drug clearance to the volume of distribution, such that:
Elimination rate constant is the major determinant of:
(1) time to reach steady state
(2) time for drug elimination
(3) dosing interval
k = ((clearance) / (volume of distribution)) =
= (0.693 / (drug half-life))
For drugs eliminated by renal excretion, k shows a linear relationship to creatinine clearance. This makes k a more useful parameter on which to base calculations of changes in drug elimination that occur with a known reduction in creatinine clearance with renal insufficiency.
If volume of distribution is very large, then elimination proceeds slowly.
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