151-200 ||151. If the dose-response curves of a drug for producing different actions are widely separated on the dose axis, the drug is .

 

GENERAL PHARMACOLOGY

151-200 || GENERAL PHARMACOLOGY QUESTIONS AND ANSWERS.



151. If the dose-response curves of a drug for producing different actions are widely separated on the dose axis, the drug is


(a) Highly potent
(b) Highly efficacious
(c) Highly toxic
(d) Highly selective


152. The therapeutic index of a drug is a measure of its


(a) Safety
(b) Potency
(c) Efficacy
(d) Dose variability


153. If the effect of combination of two drugs is equal to the sum of their individual effects, the two drugs are exhibiting


(a) Potentiation
(b) Synergism
(c) Cross tolerance
(d) Antagonism


154. The antagonism between adrenaline and histamine is called ‘Physiological antagonism’ because


(a) Both are physiologically present in the body
(b) They act on physiological receptors
(c) Both affect many physiological processes
(d) They have opposite physiological effects


155. A drug ‘R’ producing no response by itself causes the log dose-response curve of another drug ‘S’ to shift to the right in a parallel manner without decreasing the maximal response : Drug ‘R’ is a


(a) Partial agonist
(b) Inverse agonist
(c) Competitive antagonist
(d) Noncompetitive antagonist


156. A drug which does not produce any action by itself but decreases the slope of the log dose-response curve and suppresses the maximal response to another drug is a


(a) Physiological antagonist
(b) Competitive antagonist
(c) Noncompetitive antagonist
(d) Partial agonist


157. A drug which is generally administered in standard doses without the need for dose individualization is


(a) Insulin
(b) Mebendazole
(c) Prednisolone
(d) Digoxin


158. A fixed dose combination preparation meant for internal use must not contain the following class of drug


(a) Thiazide diuretic
(b) Fluoroquinolone antimicrobial
(c) Corticosteroid
(d) H2 blocker


159. Interindividual variations in equieffective doses of a drug are most marked if it is disposed by


(a) glomerular filtration
(b) Tubular secretion
(c) Both (a) and (b)
(d) Hepatic metabolism


160. The pharmacokinetics of drugs in the neonate differs from that in adults, because their


(a) Intestinal transit is fast
(b) Glomerular filtration rate is high
(c) Tubular transport mechanisms are not well developed
(d) Drug metabolizing enzymes are overactive


161. Pharmacodynamic tolerance may involve changes in _____of drug receptors


(a) Number
(b) Affinity
(c) Function
(d) All the above


162. Drug metabolism can be induced by the following factors except


(a) Cigarette smoking
(b) Acute alcohol ingestion
(c) Exposure to insecticides
(d) Consumption of charcoal boiled meat


163. Which of the following is true of placebos


(a) Placebo is a dummy medication
(b) Placebo is the inert material added to the drug for making tablets
(c) Placebos do not produce any effect
(d) All patients respond to placebos


164. In patients of hepatic cirrhosis


(a) The extent of change in pharmacokinetics of drugs can be predicted from the values of liver function tests
(b) High doses of furosemide can be safely used
(c) Metformin is the preferred oral hypoglycemic
(d) Disposition of atenolol is not significantly affected


165. An undesirable effect of a drug that occurs at therapeutic doses and can be predicted from its pharmacological actions is called


(a) Side effect
(b) Toxic effect
(c) Allergic reaction
(d) Idiosyncrasy


166. Which of the following is a type II (unpredictable) adverse drug reaction


(a) Side effect
(b) Toxic effect
(c) Idiosyncrasy
(d) Physical dependence


167. A ‘toxic effect’ differs from a ‘side effect’ in that


(a) It is not a pharmacological effect of the drug
(b) It is a more intense pharmacological effect that occurs at high dose or after prolonged medication
(c) It must involve drug induced cellular injury
(d) It involves host defense mechanisms


168. Which of the following statements is true in relation to ‘drug toxicity’ and ‘poisoning’


(a) The two terms are synonymous
(b) When a toxic effect requires specific treatment, it is called poisoning
(c) A toxic effect which endangers life by markedly affecting vital functions is called poisoning
(d) Toxicity is caused by drugs while poisoning is caused by other harmful chemicals


169. The most vulnerable period of pregnancy for the causation of foetal malformations due to drugs is


(a) 18–55 days of gestation
(b) 56–84 days of gestation
(c) Second trimester
(d) 36 weeks onwards


170. Which of the following is a proven human teratogen


(a) Chloroquine
(b) Warfarin sodium
(c) Dicyclomine
(d) Methyldopa


171. Select the drug which has been found to be a strong human teratogen


(a) Isoniazid
(b) Isotretinoin
(c) Hydralazine
(d) Propylthiouracil


172. Oral route


(a) Yields better absorption than parenteral administration for majority of drugs
(b) Should be avoided in the recumbent position
(c) Has no demerit
(d) Produces quick onset of action


173. Intramuscular route


(a) Always produces faster absorption than oral route
(b) Can be used to inject mild irritants
(c) In a child is made into the gluteus maximus muscle
(d) Can be used to inject a volume of 15 ml


174. Advantage of sublingual route include the following except


(a) It has a rapid onset of action
(b) Spitting out the tablet can terminate its action
(c) Its usefulness is limited to treat local conditions
(d) It avoids first pass hepatic metabolism


175. First pass metabolism


(a) Can increase the oral bio-availability of the drug
(b) Occurs only in the liver
(c) Is higher on intravenous administration
(d) Necessitates high oral dose for certain drugs


176. Bio-transformation


(a) Renders the drug more lipid soluble
(b) Can be altered by drugs
(c) Is necessary for all drugs for their elimination
(d) Takes place only in the liver


177. Entry of a drug in the central nervous system is enhanced if the drug is


(a) Ionized
(b) More lipid soluble
(c) Given intravenously
(d) Highly plasma protein bound


178. Kinetic processes of elimination for a large number of drugs is


(a) First order
(b) First order followed by zero order
(c) Zero order followed by first order
(d) Zero order


179. A drug is said to be potent when


(a) It produces maximal response
(b) The amount needed to produce a certain response is less
(c) It produces minimal/no side effects
(d) It has a rapid onset of action


180. Spare receptors are often found among drugs that elicit


(a) Smooth muscle contraction
(b) Smooth muscle relaxation
(c) Secretion
(d) Cardiac stimulation


181. What is the best criterian for judging the therapeutic superiority of a drug over its congeners?


(a) Potency
(b) Wide range of activity
(c) Efficacy
(d) Variability


182. pKa of a compound


(a) Is the pH of solution at which the compound is 50% ionized
(b) Is the pH of compound at which it is 50% ionized
(c) Is the time in which the compound is ionized
(d) Is the time in which total compound is ionized


183. Pharmacokinetics is


(a) The study of absorption, distribution, metabolism and excretion of drugs
(b) The study of biological and therapeutic effects of the drugs
(c) The method of development of new pharmacological agent
(d) The study of carcinogenic activity of a new drug


184. In which form the drug is absorbed more rapidly?


(a) In aqueous solution
(b) In suspension
(c) In oily solution
(d) In solid form


185. Alcohol is rapidly absorbed from the intestine because


(a) It is lipid soluble and non-electrolyte
(b) It is lipid soluble and highly ionised
(c) It is absorbed by active transport
(d) It is not absorbed quickly


186. After intramuscular injection, the drugs


(a) In oily solution are more rapidly absorbed
(b) In aqueous solution are more rapidly absorbed
(c) Suspended in various repository vehicles are more rapidly absorbed
(d) All solutions are rapidly absorbed


187. Bio-availability of a drug is


(a) The percentage of drug released from a formulation that becomes available for biological effect
(b) The percentage of drug that is ionized from a formulation
(c) The net amount of actual therapeutic agent present in the formulation
(d) The dose of a drug by which 50% animals show signs of toxicity


188. The absorption time of a drug can be reduced by


(a) Making a more soluble salt – for oral
(b) By using hyaluronidase – for injection
(c) By using vasoconstrictor substances
(d) By giving combination of drugs


189. Reduction of heavy metal toxicity by dimercaprol is an example of


(a) Chemical antagonist
(b) Physiological antagonist
(c) Pharmacokinetic antagonist
(d) Antagonism by receptor block


190. Which of the following drugs is primarily stored in the natural fat of the body


(a) Primaquine
(b) Acetyl salicylic acid
(c) Thiopentone
(d) Vitamin C


191. Bio-transformation of the drugs is to render them


(a) Less lipid soluble
(b) More protein bound
(c) Less ionized
(d) Less protein bound


192. Drug metabolism occurs chiefly in


(a) Liver
(b) Brain
(c) Spleen
(d) Kidneys


193. For renal excretion the factors important are
(a) Extent of plasma protein binding of drugs
(b) Glomerular filtration rate
(c) Active renal tubular reabsorption
(d) All of the above


194. If tubular urine is made more acid


(a) Excretion of weak acid is reduced
(b) Excretion of weak acid is increased
(c) Excretion of weak base is increased
(d) Excretion of weak base is reduced


195. Simultaneous administration of two drugs may – (select the false statement)


(a) Show an additive effect
(b) Produce synergism
(c) Result in antagonism
(d) Produce any of above phenomena


196. The advantages of bio-assay over chemical assay include – (select false statement)


(a) It is cheaper
(b) The active principal does not have to be known
(c) The active principal does not have to be in a pure state
(d) The sensitivity may be greater


197. In presence of competitive antagonist


(a) The maximum response of agonist can never be achieved
(b) The maximum can be achieved by increasing the concentration activity
(c) Maximum can be achieved only if the antagonist is having intrinsic activity
(d) None of the above


198. The receptor concept was first introduced by


(a) J.N. Langley in 1878
(b) Paul Ehrlich in 1926
(c) Somonis in 1964
(d) Wakesman in 1826


199. True tolerance develops because of


(a) Diminition in absorption
(b) Rapid excretion of the drug
(c) Both of the above
(d) None of the above


200. Two drugs binding to the same receptors is


(a) Chemical antagonism
(b) Pharmacokinetic antagonism
(c) Competitive antagonism
(d) Non-competitive antagonism




ANSWERS


151. d 
152. a 
153. b 
154. d 
155. c 
156. c 
157. b 
158. c 
159. d 
160. c 
161. d 
162. b 
163. a 
164. d 
165. a 
166. c 
167. b 
168. c 
169. a 
170. b 
171. b 
172. b 
173. b 
174. c 
175. d 
176. b 
177. b 
178. a 
179. b 
180. a 
181. b 
182. a 
183. a 
184. a 
185. a 
186. b 
187. a 
188. a 
189. a 
190. b 
191. a 
192. a 
193. d 
194. a 
195. d 
196. a 
197. b 
198. a 
199. d 
200. c


 161. d Pharmacodynamic tolerance involves multiple mechanism such as number, affinity and function of receptors.

180. a Spare receptors are generally found whenever a receptor acts catalytically and not stoichiometrically. Hence, they are generally found among drugs, which elicit smooth muscle contraction.


189. a Dimercaprol interacts directly with heavy metals in blood and tissue fluids and prevents binding of heavy metals to cellular constituents. Dimercaprol forms an inactive complex with heavy metals.


200. c Two drugs binding to the same receptor is an example of competitive antagonism and effect of one drug can be decreased by increasing the concentration of other drug.


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