Pharmacology Fundamentals Flashcards

At steady state, the rate of drug administration equals:

Answer: The rate of drug elimination

Steady state is reached when the rate of drug input equals the rate of elimination, resulting in stable plasma concentrations over time.

A drug that exhibits zero-order kinetics is eliminated at a rate that is:

Answer: Constant regardless of the plasma drug concentration

Zero-order kinetics means a constant amount of drug is eliminated per unit time, independent of plasma concentration, because elimination pathways are saturated.

Which route of administration completely bypasses first-pass hepatic metabolism?

Answer: Sublingual and intravenous

Both sublingual and intravenous routes bypass first-pass hepatic metabolism; sublingual via direct absorption into systemic veins, IV by direct entry into circulation.

Tachyphylaxis refers to:

Answer: Rapid development of tolerance upon repeated administration

Tachyphylaxis is a rapid, short-term decrease in response to a drug following repeated administration, often due to receptor desensitisation or depletion of mediators.

The loading dose of a drug is primarily determined by:

Answer: Volume of distribution and desired target concentration

The loading dose is calculated as Vd × target concentration, and is used to rapidly achieve therapeutic drug levels.

Which of the following best describes a partial agonist?

Answer: A drug that produces a submaximal response even when all receptors are occupied

A partial agonist has intrinsic efficacy but cannot produce the maximum response even at full receptor occupancy, unlike a full agonist.

Enterohepatic recycling of a drug typically results in:

Answer: Prolonged drug action due to reabsorption from the gut

Enterohepatic recycling occurs when a drug excreted in bile is reabsorbed from the intestine, cycling back to the liver and prolonging its half-life and effects.