Pharmacokinetics Quiz Questions

Pharmacology

• Streptomycin inhibits binding of penicillin to bacterial cell wall.

Mechanisms of Drug Action

• The most common mechanism of drug action is a chemical mechanism.

Pharmacogenetics and Adverse Drug Reactions

• All or non-response curve is used to calculate potency.
• Salbutamol tolerance in bronchial asthma is due to down regulation of beta-2 receptors.
• Type B adverse drug reactions are pharmacogenetic effects.

Receptors and Signaling

• Corticosteroid receptors are cytoplasmic receptors that control transcription.
• Drugs need to bind to receptors on the target cell to produce their actions.
• The fastest signaling mechanism is the ion channel mechanism.

Pharmacokinetics

• The maximal effect of the drug occurs only when the drug binds to spare receptors.
• Sublingual route of administration completely bypasses hepatic first-pass metabolism.
• The best dose interval is half-life to avoid drug concentration fluctuations.
• In zero-order kinetics, the graph of the drug concentration against time is a straight line.
• Pharmacokinetics include absorption, elimination, and distribution, but not actions.
• Half-life is the time after which plasma drug concentration is halved.

Agonists and Antagonists

• A full agonist is a drug that possesses both affinity and efficacy.
• A systemic clearance is the sum of individual organ clearances.

Metabolism and Excretion

• The most famous site for first-pass metabolism is the liver.
• The drug that is mostly eliminated by glomerular filtration is lithium.
• Lipophilic drugs can enter the CNS easily.
• Competitive antagonist at muscarinic receptors is atropine.

Pharmacological Curves

• The inverse agonist is a drug that possesses affinity and reversed efficacy.
• All-or-none response curve differs from the graded curve in that it depicts the percentage of responders against the dose.
• Efficacy of graded dose-response curve is obtained from Emax.

Tolerance and Pharmacokinetic Interactions

• Tolerance-unlike tachyphylaxis-to drugs may be due to counter-regulatory mechanisms.
• Pharmacokinetic drug interactions may be due to enzyme induction.
• Penicillin should not be mixed with aminoglycoside antibiotics in the same syringe because streptomycin inactivates penicillin.

Absorption and Distribution

• The most common method of drug absorption is passive diffusion.
• In first-order kinetics, the concentration-time relationship is described by an exponential equation.
• Pharmacokinetics is defined as the movement of drugs into, around, and out of the body.

Enzymes and Metabolism

• The most important enzyme for drug metabolism is CYT P450 oxidase.
• Bioavailability of intravenous-administered drugs is equal to 1.
• Excretion of drugs by filtration is affected by pH of urine and glomerular filtration rate.
• Absorption of oral drugs is not affected by capillary permeability or blood supply of the absorptive surface.