Pharmacotherapy 17
Pharmacokinetics
Card 1 of 13PK Basics
📖 Chapter Opening
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What the body does to the drug
Pharmacokinetics Basics
Pharmacokinetics describes absorption, distribution, metabolism, and excretion (ADME) - what the body does to the drug.
Four parameters drive dosing: bioavailability (F), volume of distribution (Vd), clearance (CL), and half-life. Pharmacodynamics is the flip side - what the drug does to the body.
The key relationships
Half-life = 0.693 x Vd / CL. Loading dose depends on Vd; maintenance dose depends on CL. Steady state is reached in ~5 half-lives.