Review of Pharmacology - 9E (2015)

Autacoids
16. Ans. (b) Dangerous ventricular arrhythmias can occur (Ref: KDT 6/e p158)
Ketoconazole, erythromycin and clarithromycin are potent inhibitors of microsomal enzymes. Astemizole, terfenadine
and cisapride are the drugs that can block cardiac K + channels at high concentration. If administered along with microsomal
enzyme inhibitors, these drugs can result in torsades de pointes, a serious polymorphic ventricular tachycardia.
17. Ans. (c) It does not block cardiac K + channels (Ref: KDT 6/e p158)
Fexofenadine is an active metabolite of terfenadine. It lacks K + channel blocking property, therefore is devoid of arrhythmogenic
potential. It is available as a separate second generation H 1
blocking agent.
18. Ans. (d) Azelastine (Ref: KDT 6/e p159)
19. Ans. (c) 5-HT 3
(Ref: KDT 6/e p163)
All serotonin receptors are G-protein coupled receptors except 5-HT 3
, which is an inotropic receptor.
20. Ans. (a) 5-HT 1A
(Ref: KDT 6/e p163)
21. Ans. (b) Serotonin 5-HT 3
receptor (Ref: KDT 6/e p163)
22. Ans. (d) Tegaserod (Ref: KDT 6/e p654)
Both cisapride and tegaserod are selective 5HT 4
agonists useful in the treatment of GERD. Cisapride possesses cardiac K +
channel blocking activity and can lead to torsades de pointes. Tegaserod is devoid of this adverse effect. However, tegaserod
has recently been withdrawn due to increased risk of MI and stroke.
23. Ans. (b) Adrenaline (Ref: KDT 6/e p129)
• Adrenaline is a physiological antagonist of histamine. It reverses bronchoconstriction caused by histamine. Ranitidine
is an H 2
antagonist that decreases gastric acid secretion but has no effect on smooth muscles.
24. Ans. (c) Common cold (Ref: KDT 6/e p160)
In this condition, excessive secretions (like rhinorrhoea) are due to cholinergic overactivity. First generation antihistaminics
possess anticholinergic property and therefore are effective for common cold. On the other hand, second generation
agents (lacking anticholinergic actions) are ineffective.
25. Ans. (d) Treatment of these patients with erythromycin, a macrolide antibiotic (Ref: KDT 6/e p158)
Astemizole and terfenadine are metabolized by microsomal enzymes. Erythromycin inhibits these enzymes and raises the
plasma concentration of these drugs. At high levels, these agents block cardiac K + channels leading to arrhythmias.
26. Ans. (d) Cinnarizine (Ref: KDT 6/e p156)
27. Ans. (b) 5HT 2
antagonist (Ref: KDT 6/e p167)
28. Ans. (a) Chlorpheniramine (Ref: KDT 6/e p156-157)
29. Ans. (a) Ketoconazole (Ref: KDT 6/e p763)
30. Ans. (b) Lanreotide (Ref: KDT 6/e p166-167)
Lanreotide is a somatostatin analog used in acromegaly.
31. Ans. (c) Diphenhydramine (Ref: Katzung 11/e p278)
Diphenhydramine and promethazine have maximum anti-cholinergic activity and maximum ability to cross the blood brain barrier
and are thus most effective in motion sickness.
32. Ans. (a) Antiemetic (Ref: KDT 6/e p646)
33. Ans. (d) Terfenadine (Ref: KDT 6/e p158)
34. Ans. (a) Gastroesophageal reflux disease (Ref: KDT 6/e p645)
35. Ans. (d) Decreasing IP 3
in stomach (Ref: KDT 6/e p153)
36. Ans. (a) Dihydroergotamine (Katzung 11/e p289)
This is a classical sign of ergot induced vasoconstriction. Dihydroergotamine can be used for acute attack of migraine and
can result in these symptoms. Due to their vasoconstricing potential, ergot alkaloids are contra-indicated in a patient with
peripheral vascular disease. These may also lead to development of gangrene.
37. Ans. (d) Levetiracetam (Ref: Katzung 11/e p283)
Prophylaxis of migraine is required if the attacks are frequent (>2-3 per month). The drugs useful for prophylaxis are:
General Autacoids Pharmacology
• Propanolol is the most commonly used drug for prophylaxis of migraine attacks. Timolol, atenolol, metoprolol
and nadolol can also be used but the drugs with ISA (e.g. pindolol) are ineffective.
• Calcium channel blockers like flunarizine (also blocks Na + channels) is also effective
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