For orally administered drugs, the minimum steady state concentration can be calculated if the kinetic parameters for the drug are known. This is the plasma level just before the next oral dose (trough).
C(min-ss) =
= (fraction drug remaining) * C(max-ss))
fraction drug remaining =
= (EXP((-1) * (elimination rate constant) * (dosing interval)))
Based on the equation for C(max-ss) it can be shown that:
= ((fraction orally absorbed) * (maintenance dose) * (fraction of dose remaining) / (volume of distribution) / (fraction of dose lost from body)) =
= ((fraction orally absorbed) * (maintenance dose) * (fraction of dose remaining) * (accumulation factor) / (volume of distribution))
fraction of dose lost from body =
= (1 - (EXP((-1) * (elimination rate constant) * (dosing interval))))
accumulation factor =
= (1 / (1 - EXP((-1) * (elimination rate constant) * (dosing interval)))
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Specialty: Toxicology, Emergency Medicine, Critical Care
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