Review of Pharmacology - 9E (2015)

Review of Pharmacology
Explanations
1. Ans (b) Cyclizine (Ref: Goodman and Gilman 12/e p921,922)
Antihistaminics may be classified into first generation and second generation compounds on the basis of CNS penetration
and anticholinergic properties. First Generation Anti-histaminics can penetrate blood brain barrier and possess additional
anticholinergic properties which are lacking in second generation drugs. Cyclizine is a first generation whereas cetririzine,
loratidine and fexofenadine are second generation drugs.
2. Ans. (c) Bradykinin (Ref: KDT 6/e p490, 491)
Although both histamine as well as bradykinin can cause edema and increase in permeability, histamine is an amine
whereas bradykinin is a peptide.
3. Ans. (a) Post partum hemorrhage (Ref: KDT 6/e p322)
Obstetric indications of ergometrine (Ergonovine):
• To control and prevent Post partum hemorrhage. It is given at the time of delivery of anterior shoulder.
• After Caesarean Section/instrumental delivery – to prevent uterine atony.
• To ensure normal involution in multipara.
Autacoids
4. Ans. (d) Cetirizine (Ref: KDT 6/e p157)
It is a non-sedating second generation antihistaminic agent and is preferred for the patients requiring constant attention.
It does not cause sedation or impairment of psychomotor function. Other drugs listed in the question are first generation
antihistaminics.
5. Ans. (a) Cyclizine (Ref: KDT 6/e p156)
6. Ans. (b) Increase in H 1
mediated gastrin release (Ref: KDT 6/e p153)
H 3
receptors act as pre-synaptic receptors and decrease the release of histamine and other neurotransmitters. These antagonize
H 1
mediated wakefulness and bronchoconstriction. These also decrease gastrin release and produce negative
chronotropic effect. Inverse agonist of H 3
receptor (tiprolisant) is approved for Narcolepsy.
7. Ans. (a) Azelastine; (b) Fexofenadine; (d) Desloratidine (Ref: KDT 6/e p158-159)
Chlorpheniramine and promethazine are first generation anti-histaminics.
8. Ans. (b) Direct action on vascular smooth muscle causing vasodilation (Ref: KDT 6/e p153)
Both H 1
and H 2
receptors cause vasodilation. H 1
receptors are present in the endothelium and cause vasodilation by
releasing NO. However, H 2
receptors are present on the smooth muscles and cause direct vasodilation.
9. Ans. (c) Morphine (Ref: KDT 6/e p155)
Basic drugs like morphine, d-TC and amphotericin B etc. act as histamine liberators and can cause acute reaction leading
to itching and hypotension.
10. Ans. (a) Promethazine (Ref: KDT 6/e p158)
All the drugs listed in the question are second generation anti-histaminic agents except promethazine.
11. Ans. (c) Cyproheptadine (Ref: KDT 6/e p166)
12. Ans. (a) Driving motor vehicles (Ref: KDT 6/e p157)
First generation antihistaminic agents cause sedation and impairment of psychomotor function.
13. Ans. (b) These possess high anti-motion sickness activity (Ref: KDT 6/e p157)
Anti-motion sickness activity is related to anticholinergic property. This property is exhibited by first generation compounds
whereas second generation antihistaminics lack this potential.
14. Ans. (c) Astemizole (Ref: KDT 6/e p158)
15. Ans. (b) Cinnarizine (Ref: KDT 6/e p160)
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