Pharmacokinetics Quiz

Pharmacokinetics and Pharmacodynamics

• The therapeutic index (TI) measures the ratio of the toxic dose to the therapeutic dose, indicating the safety margin of a drug.
• Lipid-soluble drugs are readily absorbed in the GI tract, as they can dissolve in the lipid bilayer of the intestinal epithelial cells.

Dosage Forms

• A solid dosage form prepared by compression of a homogeneous mass of particles is called a tablet.

Drug Excretion

• The excretion of weak base medications can be increased by alkalizing the urine, making the bases more ionized and traps them in the urine, thus enhancing their excretion.

Pharmacokinetics Parameters

• The plasma half-life (t ½) represents the time taken for the plasma concentration of a drug to decrease by 50%, determining the duration of action of a drug.

Definition of Pharmacokinetics

• Pharmacokinetics is the study of the movement of drugs within the body, including absorption, distribution, metabolism, and excretion.

Mechanisms of Drug Absorption

• The main mechanism of most drugs' absorption in the GI tract is passive diffusion, where the drug molecules move from an area of high concentration to an area of low concentration.

Bioavailability

• The term 'bioavailability' refers to the fraction of the administered dose of a drug that reaches the systemic circulation, determining the amount of drug available for therapeutic action.

Metabolic Transformation

• The process of metabolic transformation (phase 1) involves oxidation, reduction, and hydrolysis reactions, which convert the drug into a more polar and water-soluble metabolite.

Half-Life (t ½)

• The term 'half-life (t ½)' refers to the time taken for the plasma concentration of a drug to decrease by 50%, which is a critical parameter in determining the dosing frequency and duration of action of a drug.