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pharmacyTopic wise MCQs

General Pharmacology MCQs ( Part-9 )

General Pharmacology

1. Binding of a drug to plasma proteins will tend to:
A. Decrease half-life.
B. Decrease its rate of glomerular filtration.
C. Increase its rate of biotransformation.
D. Increase its concentration in the plasma.
E. Increase its pharmacological activity.

2. Dose-response curves are used for drug evaluation in the animal laboratory and in the clinic. Quantal dose-response curves are
A. Used for determining the therapeutic index of a drug
B. Used for determining the maximal efficacy of a drug
C. More precisely quantitated than ordinary graded dose-response curves
D. Obtainable from the study of intact subjects but not from isolated tissue preparations
E. Used to determine statistical variation (standed deviation) of the maximal response to the drug

3. Compared to the average adult dose, the recommended dose of a drug for elderly patients will likely be:
A. Less than average due to increased biotransformation.
B. Less than average due to decreased renal function or excretion
C. More than average due to decreased plasma protein binding capacity.
D. More than average due to increased renal excretion.
E. Totally unpredictable.

4. Which one of the following statements is applicable to absorption of drugs from the gastrointestinal tract?
A. Absorption of weak acids occurs only from the stomach and not from the small intestine.
B. Some drugs are metabolized extensively by the liver and do not reach the general circulation (first-pass effect)
C. All the drugs are stable at the low pH of the stomach.
D. Rectal administration is the best way to give irritating drugs.
E. Ingesting drugs with food always enhances drug absorption.

5. Which of the following statements about spare receptor is MOST correct
A. Spare receptors, in the absence of drug, are sequestered in the cytoplasm
B. Spare receptors may be detected by finding that the drug-receptor interaction longer than the intracellular effect
C. Spare receptors influence the maximal efficacy of the drug-receptor system
D. Spare receptors activate the effector machinery of the cell without the need for a drug
E. Spare receptors may be detected by the finding that the EC50 is smaller than the Kd for the agonist

6. A patient is treated chronically with a drug (A) metabolized by CYP 3A4. Recently he administer another drug (B) which is an enzymatic inducer of the CYP2D6.Which of the following is likely to occur:
A. Longer half life of drug (A)
B. Longer half life of drug (B)
C. Enhanced pharmacological effect of drug A
D. No significant drug interaction
E. Reduced pharmacological effect of drug B

7. All of the following are applicable to the concept of the blood-brain barrier EXCEPT:
A. Restricts the entry of hydrophilic compounds into the brain.
B. Has as one component, endothelial cells with pores accessible only by compounds of less than 200 Daltons.
C. Is penetrated only by organic solvents which are used as general anesthetic agents.
D. Is between the plasma space and the interstitial space of the brain.
E. Drugs which are well absorbed from the G.I.T penetrate well into the brain.

8. What happen if valproic acid ( strongly bound to albumin) and imipramine, a tricyclic antidepressant ( bound to alpha acid glycoprotein)
A. Potential toxicity of valproic acid.
B. significant increase in free level of both drugs.
C. Enhanced biotransformation of valproic acid.
D. increase in volume of distribution of imipramin
E. No interference in protein binding is expected / No pharmacokinetic drug-drug interaction is expected

9. A drug with half life of about 24h was prescribe orally at the dose of 100mg once daily. After two weeks, the dose was changed to, 200mg once daily. Following this change in treatment:
A. The mean plasma concentration doubles.
B. The plasma half life of the drug doubles
C. the difference between the maximum plasma concentration (peak) and minimal (trough) become very small.
D. the volume of distribution of the drug double.
E. The time required to reach the steady state of concentration decrease by a half

10. In general, biotransformation usually results in a product which is more:
A. Likely to produce side effects.
B. Likely to distribute intracellularly.
C. Lipid soluble than the original drug.
D. Likely to be reabsorbed by kidney tubules.
E. Water soluble than the original drug.

11. For a drug eliminated by a first-order kinetic process:
A. A constant amount of drug is eliminated per unit time.
B. The duration of action will be longer than for a drug eliminated by zero-order process.
C. The elimination rate constant will be independent of the dose administered.
D. It is unlikely to bind significantly to plasma albumin.
E. The apparent volume of distribution will vary with time.

12. Enzyme inhibitors such as Cimetidine and Erythromycin are likely to produce:
A. Increase rate of breakdown of some drugs
B. increase free level of some drugs
C. inhibition of certain enzymes which break down some drugs.
D. improvement of bioavailability of some drugs
E. Reduction the toxicity of some drugs.

13. A competitive reversible antagonist :
A. Shifts the dose-response curve of an agonist to the right.
B. Decreases the maximal response produced by agonists acting on the same receptor.
C. Produces an effect which is mathematically equivalent to decreasing the efficacy of the agonist.
D. Increases the efficacy of the agonist.
E. Binds to the receptor by covalent bonding.

14. Regarding binding of drugs to plasma albumin:
A. All drugs are strongly bound to albumin.
B. Binding of drugs enhance there therapeutic effects.
C. Binding of drugs to albumin enhance their elimenation.
D. Albumin binds reversibly certain acidic drugs.
E. drugs bound to albumin crosses membranes easily.

15. An experiment was performed to determine the median effective dose (ED50) for causing hypnosis and the median lethal dose (LD50) of a drug. The ED50 was found to be 1 mg. The LD50 was found to be 300mg. What is the therapeutic index for this drug?
A. 300.
B. 30.
C. Less than 10.
D. 3.

16. The following statement concerning pre-systemic metabolism are true except:
A. is the metabolism of administrated drugs before reaching systemic circulation.
B. it can be avoided by giving the drug via another route of administration.
C. it usually leads to decrease drug bioavailability.
D. drugs with extensive first pass effect may be ineffective orally.
E. it is usually occurs due to enzyme induction or inhibition.

17. Which of the following is a receptor that is not located on the plasma membrane?
A. Nicotinic receptor.
B. Muscarinic receptor.
C. G protein.
D. Adenylyl cyclase.
E. Steroid receptor.

18. Enzyme inducers, such as phenyoin and carbamazepine are likely to produce:
A. An increase in bioavailability of many drugs.
B. decrease of absorption of many other drugs.
C. An increase in effect of many other drugs
D. a possible acceleration of the catabolism of certain other drugs
E. a decrease in protein binding of many drugs

19. The following statements concerning drugs metabolism are true. Except:
A. Metabolites are generally more polar than parent drug.
B. metabolites are usually inactive or less active than the parent drug.
C. neonates have deficiency in phase II (conjugation) metabolic pathway.
D. metabolizing enzyme can’t be inhibited by other drugs.
E. the rate of metabolism by certain CYP are genetically.

20. Substances strongly suspected or known to be capable of harming the fetus when consumed by a pregnant woman include all of the following EXCEPT:
A. Sex hormones.
B. Oral anticoagulants (warfarin).
C. Alcohol.
D. Anticancer (cytotoxic) drugs.
E. Penicillins.

21. Which of the following names best describes an antagonist that interacts directly with the agonist and not at all, or only incidentally, with the receptor
A. Chemical antagonist
B. Noncompetitive antagonist
C. Partial agonist
D. Pharmacologist antagonist
E. Physiologic antagonist

22. The following route of administration is likely to associated with significant first pass effect observed with certain drugs:
A. oral
B. sublingual
C. intramuscular
D. Rectal
E. transdermal.

23. All of the following statements regarding adverse drug reactions are correct EXCEPT?
A. Pharmacokinetic mechanisms are unimportant in causation.
B. Young children cannot be regarded as “small adults” as far as liability to adverse drug reactions is concerned.
C. The first few weeks of life is a period of special risk.
D. Old age is a period of special risk.
E. Atmospheric pollution in hospitals may be a cause.

24. All the following statements regarding adverse drug reactions are correct EXEPT:
A. Pharmacokinetic mechanisms are unimportant in causation.
B. Young children cannot be regarded as “small adults” as far as liability to adverse drug reactions is concerned.
C. The first few weeks of life is a period of special risk.
D. Re-exposure to a small dose is enough to cause illness.
E. Atmospheric pollution in hospitals may be a cause.

25. Which of the following provides information about the variation in sensitivity to a drug within the population studied
A. Drug potency
B. Graded-dose-response curve
C. Maximal efficacy
D. Quantal dose-response curve
E. Therapeutic index

26. kinetic that are characteristic of elimination of ethanol, high dose of aspirin and phenytoin are called:
A. distribution
B. excretion
C. first pass effect
D. first order elimination
E. zero order elimination

27. The following statements concerning renal elimination of drug are true. Except:
A. alklinization of urine will enhance elimination certain acidic drugs.
B. measurement of creatinine clearance can be used for assessment of renal function.
C. some drugs are mainly eliminated by kidney
D. renal elimination is greatly affected by age & gender.
E. most drugs are eliminated by active tubular secretion

28. All of the following are phase I biotransformation reactions EXCEPT:
A. Sulfoxide formation.
B. Sulfate conjugation.
C. Nitro reduction.
D. Ester hydrolsis.
E. Deamination.

29. Important manifestations of drug allergy include all of the following EXCEPT:
A. Thrombocytopenia.
B. Leukemia.
C. Aplastic anemia.
D. Hemolysis.
E. Granulocytopenia.

30. Which of the following most accurately describes the transmembrane signaling process involved in steroid hormone action?
A. Action on a membrane-spanning tyrosine kinase?
B. Activation of G protein, which activates or inhibits adenyl cyclase.
C. Diffusion across the membrane and binding to an intracellular receptor.
D. Diffusion of STAT molecules across the membrane.
E. Opening of the transmembrane ion channnel.

31. Variation in the sensitivity of a population of individuals to increasing doses of a drug is best determined by which of the following?
A. Efficacy
B. Potency
C. Therapeutic Index
D. Graded dose-response curve
E. Quantal dose-response curve

32. In the absence of other drugs, pindolol causes an increase in heart rate by activating beta adrenoceptors. In the presence of highly effective beta stimulants. However, pindolol causes a dose-dependant, reversible decrease in heart rate. Therefore, pindolol should be classified as
A. A chemical antagonist
B. An irreversible antagonist
C. A partial agonist
D. A physiologic antagonist
E. A spare receptor agonist

33. All of the following statements related to the binding of drugs by plasma proteins are correct EXCEPT?
A. Bound drug is unable to diffuse into tissue until it becomes unbound.
B. A drug that is bound by plasma proteins will have a smaller apparent volume of distribution than if it were not bound.
C. Displacement of the bound drug by another drug can increase the effects of a given dosage of the first drug.
D. Acidic drugs are bound mostly to plasma albumin.
E. bound drug is the pharmacologically active part of the drug.

34. The term that refers to the rapid diminution of responsiveness following administration of a drug is:
A. Hyporeactivity.
B. Tachyphylaxis.
C. Idiosyncratic drug response.
D. Tolerance.
E. Drug inactivation.

35. Correct statements concerning characteristics of a particular route of drug administration include all of the following EXCEPT:
A. Intravenous administration provides a rapid response.
B. Oral administration requires that the patient be alert.
C. Intramuscular administration requires sterile technique.
D. Subcutaneous administration may cause local irritation.
E. Inhalation provides slow access to the general circulation.

36. Factors affecting drug bioavailability include the following except:
A. its physiochemical properties ( molecular weight, stability in GIT etc)
B. binding of drugs to plasma protein ( albumin or a-acid glycoprotein)
C. dosage form ( table, syrup etc)
D. physiological & pathological variables ( gastric emptying time, diarrhea)
E. its interaction with food or other drugs.

37. Which one of the following is TRUE for a drug whose elimination from plasma shows first-order Kinetics?
A. The half-life of the drug is proportional to the drug concentration in the plasma.
B. The amount eliminated per unit time is constant.
C. The rate of elimination is proportional to the plasma concentration.
D. Elimination involves a rate-limiting enzymic reaction operating at its maximal velocity (Vm).
E. A plot of drug concentration versus time is a straight line .

38. According to alphabetical classification of types of adverse drug effects, anaphylaxis from penicillin injection is an adverse drug effect type:
A. A.
B. B.
C. C.
D. D.
E. E.

39. All of the following statements are true EXCEPT:
A. Aspirin (pka=3.5) is 90% in its lipid-soluble, protonated form at pH=2.5.
B. Absorption of a weakly basic drug is likely to occur faster from the intestine than from the stomach.
C. The basic drug promethazine ( pKa=9.1) is more ionized at pH =7.4 than at pH=2.
D. Acidification of the urine accelerates the secretion of a weak base, pKa=8.
E. Uncharged molecules more readily cross cell membranes than charged molecules.

40. In pregnancy the following statements are correct EXCEPT:-
A. Gross anatomical defects in the fetus are unlikely to result from drugs in late pregnancy.
B. Sex hormones, when taken during pregnancy, may harm the fetus.
C. A vasoconstrictor drug may cause fetal distress.
D. Cytotoxic or anticancer drugs given to the mother are safe during pregnancy.
E. Teratogenic drugs may produce harmful effect, especially if given in early pregnancy.

41. All of the following drugs are hepatic microsomal enzyme inducers EXCEPT:-
A. Phenobarbitone.
B. Phenylbutazone.
C. Phenytoin.
D. Rifampin.
E. Cimetidine.

42. The following reactions are related to pharmacogenetic abnormalities EXCEPT:-
A. Succinylcholine apnea.
B. Slow and fast acetylation of isoniazed and sulfonamide.
C. Glucose -6- phosphate dehydrogenase deficiency induced hemolytic anemia after exposure to primaquine.
D. Increased resistance to the anticoagulant action of warfarin.
E. Bradycardia due to β- adrenoreceptor antagonists.

43. Drug X and Y have the same mechanism of antihypertensive action. Drug X in a dose of 10 mg produces the same response as 100 mg of drug Y. This suggests that:
A. Drug Y is less efficacious than drug X.
B. Toxicity of drug X is less than that of drug Y.
C. Drug X is about 10 times more potent than drug Y.
D. Drug X is safer than drug Y.
E. Drug X will have a shorter duration of action than drug Y because less of drug X is present for a given time.

44. Which of the following are methods for avoiding “first-pass “metabolism of the drug by the liver ?
A. Subcutaneous injection of epinephrine.
B. Sublingual administration of nitroglycerin.
C. Intramuscular administration of propranolol.
D. Transdermal application of nitroglycerin.
E. All of the above.

45. A 55-year-old woman with heart failure is to be treated with a diuretic drug. Drugs X and Y have the same mechanism of diuretic actions. Drug X in a dose of 5 mg produces the same magnitude of dieresis as 500 mg of drug Y. this suggests that :
A. drug Y is less efficacious than drug X
B. drug X is about 100 times more potent than drug Y
C. toxicity of drug X is less than that of drug Y
D. drug X is a safer drug than drug Y
E. drug X will have shorter duration of action than drug Y because less of drug X is present for a given effect

46. Concerning drug-plasma protein binding:
A. Volume of distribution is not influenced by protein binding
B. Drug clearance is not influenced by the extent of protein binding
C. Drug-plasma albumin binding is usually highly selective
D. Renal failure may decrease drug bound fraction because of reduced plasma albumin
E. Drugs are seldom bound to plasma proteins

47. Termination of pharmacological action of thiopental occurs mainly by:
A. Metabolism
B. Rabid excretion
C. Redistribution
D. Strong binding to plasma protein
E. Inactivation in the brain tissues

48. Characteristics of drug conjugates (following conjugation reactions)
A. Are more polar compounds
B. Are less readily excreted
C. Are typically more pharmacologically active
D. Usually occurs in the kidneys
E. Usually involve hydrolysis , oxidation and reduction

49. Cytochrome P450 induction (increased, amount of P450 enzyme protein) is often associated with:
A. Increased enzyme synthesis rates and metabolism for certain drugs
B. Redacted enzyme synthesis rates and metabolism for certain drugs
C. Enhanced protein binding for certain drugs
D. Enhanced bioavailability for certain drugs
E. Prolonged half-life for certain drugs

50. Features that influence drug bioavailability include all of the following except :
A. First pass hepatic metabolism
B. Lipid solubility of the drug
C. Chemical stability of the drug
D. Nature of drug formulation
E. plasma protein binding of the drug