Test your basic pharmacology: drug absorption, distribution, metabolism and excretion, receptors, agonists and antagonists, and drug interactions. There are two sets of 10 questions. Click an answer to see whether you are right, with a short explanation.
Set 1: Basic Pharmacology I
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1.All of the following are general mechanisms of drug permeation EXCEPT:
Answer: D. Drugs cross membranes by aqueous diffusion, lipid diffusion, carrier-mediated transport and endocytosis or pinocytosis. Hydrolysis is a metabolic reaction, not a way of crossing membranes.
2.Distribution of a drug to a specific tissue:
Answer: A. Only unbound (free) drug diffuses into tissues, so the free-drug gradient drives distribution. Blood flow and tissue solubility also matter, and a large volume of distribution lengthens half-life.
3.The process by which a weak acid becomes less water-soluble and more lipid-soluble at low pH is:
Answer: C. At low pH a weak acid (HA) gains a proton and becomes un-ionized, which makes it more lipid-soluble.
4.Which drugs are excreted faster in basic (alkaline) urine?
Answer: D. In alkaline urine weak acids are ionized, so they are trapped in the urine and less reabsorbed. This is why urine is alkalinized in aspirin or phenobarbital overdose.
5.A drug that blocks epinephrine by occupying its receptors without activating them is a:
Answer: C. A pharmacological (receptor) antagonist binds the same receptor without activating it. A physiological antagonist acts on a different receptor to cause an opposing effect.
6.Which drug may inhibit the hepatic cytochrome P450 enzymes that metabolize warfarin?
Answer: B. Cimetidine inhibits several CYP enzymes and can raise warfarin levels. Phenobarbital, rifampicin and chronic alcohol use induce CYP enzymes.
7.Which provides information about the variation in sensitivity to a drug within the population studied?
Answer: A. A quantal dose-response curve plots the proportion of the population showing a defined response at each dose, so it shows how sensitivity varies between individuals.
8.Which of these is a Phase II drug-metabolizing reaction?
Answer: B. Acetylation is a conjugation (Phase II) reaction, for example of isoniazid. Deamination, hydrolysis and oxidation are Phase I reactions. Medicinal chemistry quiz →
9.A good example of chemical antagonism is:
Answer: A. Positively charged protamine binds negatively charged heparin directly and neutralizes it. Atropine and acetylcholine is pharmacological (receptor) antagonism.
10.Phenylephrine causes:
Answer: D. Phenylephrine is a selective alpha-1 agonist. It constricts blood vessels, which is why it is used as a nasal decongestant.
Set 2: Basic Pharmacology II
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1.Which factors determine the distribution of a drug from the blood into tissues?
Answer: C. Blood flow, the drug's solubility in the tissue, its concentration in the blood and its binding to plasma and tissue proteins all affect distribution.
2.Most drug receptors are:
Answer: A. Most receptors are proteins: G protein-coupled receptors, ion channels, enzyme-linked receptors and intracellular (nuclear) receptors.
3.Which route of administration gives the most rapid onset of effect?
Answer: B. IV injection puts the drug directly into the circulation with no absorption step and 100% bioavailability.
4.Acidic drugs mainly bind to which plasma protein?
Answer: C. Acidic drugs such as warfarin, phenytoin and NSAIDs bind mainly to albumin. Basic drugs such as lidocaine and propranolol bind to alpha-1 acid glycoprotein.
5.After oral administration, most drugs are best absorbed from the:
Answer: A. The small intestine has a very large surface area and high blood flow, so most absorption happens there, even for weak acids.
6.Creatinine clearance is used to estimate the:
Answer: C. Creatinine is freely filtered and only slightly secreted, so its clearance approximates GFR. It is used to adjust doses of renally cleared drugs.
7.The renal clearance of inulin is used to measure the:
Answer: D. Inulin is freely filtered and is neither reabsorbed nor secreted, so its clearance equals GFR. Para-aminohippurate (PAH) clearance measures effective renal plasma flow.
8.Which tissue has the greatest capacity to biotransform drugs?
Answer: A. The liver has the highest concentration of drug-metabolizing enzymes, including the cytochrome P450 system.
9.Which drug is the agent of choice for anaphylactic reactions?
Answer: C. Intramuscular epinephrine reverses bronchospasm, vasodilation and hypotension in anaphylaxis. Ipratropium and propantheline are antimuscarinics; edrophonium is a cholinesterase inhibitor.
10.Hydrolysis is involved in the metabolism of all of the following EXCEPT:
Answer: D. Procaine and aspirin are esters and lidocaine is an amide, all hydrolysed. Diazepam is metabolized mainly by CYP-mediated oxidation (N-demethylation and hydroxylation). Medicinal chemistry quiz →