Pharmacology Fundamentals Flashcards
7 cards from real KAPS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Pharmacology Fundamentals flashcards as text
At steady state during continuous IV infusion, the plasma drug concentration is primarily determined by:
Answer: The infusion rate and the drug's clearance
At steady state, the rate of drug input equals the rate of elimination, so steady-state concentration (Css) = infusion rate / clearance.
A competitive antagonist shifts the agonist dose-response curve in which direction?
Answer: To the right (increases EC50) without changing Emax
Competitive antagonists increase the EC50 (shift curve rightward) but the maximal effect remains unchanged because higher agonist concentrations can overcome the blockade.
Which statement correctly describes zero-order elimination kinetics?
Answer: A constant amount of drug is eliminated per unit time
Zero-order (saturation) kinetics occurs when elimination pathways are saturated, resulting in elimination of a constant amount of drug per unit time, not a constant fraction.
Which of the following drug properties most strongly promotes distribution of a drug into the CNS?
Answer: High lipophilicity and low plasma protein binding
CNS penetration is favored by lipophilicity (allowing passage through the blood-brain barrier lipid bilayer) and low protein binding (increasing free drug fraction).
A patient is a 'poor metabolizer' for CYP2C19. When prescribed a prodrug that requires CYP2C19 activation (e.g., clopidogrel), the expected clinical outcome is:
Answer: Reduced therapeutic effect due to inadequate prodrug activation
Poor CYP2C19 metabolizers cannot efficiently convert clopidogrel to its active thiol metabolite, resulting in reduced antiplatelet efficacy and higher risk of cardiovascular events.
The Henderson-Hasselbalch equation is used in pharmacology to predict:
Answer: The ionization state of a drug at a given pH and its impact on absorption
The Henderson-Hasselbalch equation relates pH, pKa, and the ratio of ionized to unionized drug, predicting the degree of ionization that determines membrane permeability and absorption.
Which term describes a drug interaction where two drugs produce an effect greater than the sum of their individual effects?
Answer: Synergism (potentiation)
Synergism (or potentiation) occurs when the combined effect of two drugs exceeds the arithmetic sum of their individual effects, often exploited therapeutically in combination regimens.