Pharmacokinetics, Pharmacodynamics, Pharmacology of Autonomic nervous system drugs, Autocoids
51. The general pharmacological properties of non-catechol sympathomimetic amines include:
a. T
b. T
c. T
d. F: causes tachycardia.
52. The following refers to the acetylator status of individuals:
a. F: it is a bimodal frequency distribution.
b. F
c. F: toxicity is more likely with fast acetylators
d. T: 80% Chinese, 60% Malays and 25% Indians are fast acetylators.
53. Malathion:
a. F
b. F: forms a stable complex with cholinesterase, preventing the hydrolysis of acetylcholine causing it to accumulate at neuromuscular junction.
c. T
d. T
54. Hyoscine:
a. F: it is an antimuscarinic agent.
b. F: it produces CNS depression unlike atropine which has stimulant effects.
c. T: it causes mydriatic which can lead to an increase in intraocular pressure.
d. T
55. The bioavailability of a drug:
a. T
b. F: refers to the rate and extent of unchanged drug absorbed into the systemic circulation from a particular dosage form.
c. F
d. T
56. With regards to gastrointestinal absorption of drugs:
a. T: however, the small intestines still account for the large percentage of absorption of acidic drugs due to its large surface area.
b. F: causes delayed absorption of the drug.
c. F: calcium forms chelates with tetracycline, reducing its absorption.
d. T: digoxin is poorly insoluble; a rapid transit rate will mean less time for its dissolution.
57. Thiopentone is ultra-short acting because it undergoes:
a. F
b. F
c. T: thiopentone rapidly diffuses out of the brain and re-distributes into the peripheral sites and consequently, its effects in the brain is rapidly terminated.
d. F
58. With regards to biotransformation of drugs by the liver:
a. F: children usually have adult metabolizing capacity; they may also have higher than adult capacity for clearance of drugs like theophylline.
b. F: overdosage is more likely as the metabolizing capacity of the drug is more likely to reach saturation.
c. T
d. T: clearance is sensitive to changes in hepatic blood flow.
59. Drugs which undergo capacity-limited metabolism:
a. F: usually have low therapeutic index.
b. F
c. T: at higher dosage, half-life will be prolonged when saturation is reached; on the other hand, half-life of drugs eliminated by first-order kinetics depends on the drug concentration in the body and not on the dosage.
d. F: they are aspirin, alcohol, phenytoin and theophylline.
60. The MFO system:
a. T
b. T
c. T: the toxic metabolite is NABQI which binds to -SH groups of hepatic cells causing cell necrosis.
d. T