Review of Pharmacology - 9E (2015)

1. Ans. (c)
explanations
1. Ans. (c) Drug B is less potent and more efficacious than drug C (Ref: KDT 7/e p54-55)
Potency is the dose at which the response is half of the maximum. More the curve is towards left, greater is the potency. In this
question, drug A is most potent followed by drug C and the drug B is least potent.
Efficacy is determined by the height of dose response curve. In this question, drug A and B have high efficacy whereas drug C
is the least efficacious.
2. Ans. (d) Instead of 100 mg, drug X should be given in divided doses. (Ref: Goodman Gilman 12/e p35)
C max
is the maximum plasma concentration obtained. In this questin, C max
is 27 µg/dl.
T max
is the time to reach C max
. It tells about rate of absorption. From the given graph, T max
is 4 hours.
AUC reflects extent of absorption and not the rate of absorption.
This drug, when given as 100 mg, produce a C max
which is higher than the minimum toxic concentration (20 µg/dl.). Thus
to avoid the toxic effects, C max
must be lower and to produce a lower C max
, the dose has to be reduced.
3. Ans. (c) Botulinum toxin (Ref: KK Sharma 2/e p211)
As shown in the diagram, the drug is inhibiting the exocytosis of ACh. Botulinum toxin act by this mechanism. Other
features pointing towards botulinum toxin are :
• Anticholinergic adverse effects (dry mouth, blurring of vision)
• Use in wrinkles, spastic disorders, prophylaxis of migraine.
4. Ans. (c) Doxazosin (Ref: KK Sharma 2/e p182–183)
The diagram is showing vasomotor reversal of Dale. Thus drug A should be α-blocker. Tamsulosin is selective α 1A
blocker
and has minimal effect on blood pressure whereas doxazosin blocks both α 1A
and α 1B/D
receptors.
5. Ans. (d) Quinidine (Ref: KK Sharma 2/e p301)
This drug is decreasing the slope of phase 0 (Na + channel blocking property) as well as increasing the action potential
duration (K + channel blocking property). Thus, it exhibits the properties of class Ia anti-arrhythmic agents like quinidine.
6. Ans. (a) (Ref: KK Sharma 2nd/265)
ACE inhibitors decrease angiotenisn II by inhibiting the conversion of Ang I to Ang II and thus aldosterone also decrease.
Due to compensatory increase in plasma renin activity, renin and angiotensin I levels increase. By inhibiting the metabolism
of bradykinin, the level of these vasoactive peptides also increase.
7. Ans. (c) (Ref: Katzung 11/e p349)
The drug zafirlukast is a cys-LT receptor antagonist.
8. Ans. (a) A (Ref: Katzung 11/e p598)
The patient is having neutropenia and the drug most likely being discussed about is ticlopidine. Clopidogrel and ticlopidine
act as ADP antagonists.Ticlopidine is rarely used due to the occurrence of serious side effects like neutropenia that
typically presents with fever and mouth ulcers. Though this is rare, it is a serious complication and complete blood count
should be monitored biweekly for the first three months.
9. Ans. (b) B (Ref: KK Sharma 2/e p633)
This is a case of diabetic coma due to diabetic ketoacidosis (DKA). The insulin of choice for DKA is regular insulin
by intravenous route. Curve A shows rapidly acting inslulins like aspart, glulisine and lispro (onset in 15-20 min.).
However, these are given by subcutaneous route and not the first choice in diabetic ketoacidosis. Curve B represents
regular insulin that can be given i.v. and is insulin of choice for DKA. Curve C represents ultralente and curve
D represents insulin glargine.
10. Ans. (d) D (Ref:KK Sharma 2/e p635)
Curve D represents the ultra-long acting insulin also known as peakless insulin as glargine and detemir.
11. Ans. (a) High blood: gas partition coefficient (Ref:Katzung 11/e p427)
• The depth of anesthesia depends on the partial pressure of anesthetic in CNS. The transfer of anesthetic into the brain
starts only after the blood is fully saturated (or, in other words partial pressure of the anesthetic in blood equals the
partial pressure in the inspired air). The speed of transfer of anesthetic to the brain determines its onset of action
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