The half-life of a drug is the time needed for the concentration of the drug to decrease by half.
T(half) =
= (0.693 / (elimination rate constant)) =
= (0.693 * (volume of distribution) / (clearance))
Half-life is determined by both clearance and the volume of distribution:
(1) The half-life increases with reduced clearance.
(2) The half-life decreases with increased clearance (for example, with enzyme induction).
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Specialty: Toxicology, Emergency Medicine, Critical Care
ICD-10: ,
