دانلود کتاب بررسی های مصور Lippincott: فارماکولوژی – ویرایش هشتم

Pharmacokinetics refers to what the body does to a drug, whereas pharmacodynamics (see Chapter 2) describes what the drug does to the body. Four pharmacokinetic properties determine the onset, intensity, and duration of drug action (Figure 1.1): Absorption: First, absorption from the site of administration permits entry of the drug (either directly or indirectly) into plasma. Distribution: Second, the drug may reversibly leave the bloodstream and distribute into the interstitial and intracellular fluids. Metabolism: Third, the drug may be biotransformed through metabolism by the liver or other tissues. Elimination: Finally, the drug and its metabolites are eliminated from the body in urine, bile, or feces. Using knowledge of pharmacokinetic parameters, clinicians can design optimal drug regimens, including the route of administration, dose, frequency, and duration of treatment.