Review of Pharmacology - 9E (2015)

Autonomic Nervous System
9. Ans. (a) Timolol (Ref KDT 6/e p139)
Timolol is a non-selective beta blocker and can precipitate acute attacks of asthma in a susceptible individual via blockade
of b 2
receptors. Betaxolol is a cardioselective beta blocker and is less likely to cause this adverse effect.
10. Ans. (b) Clozapine (Ref: Katzung 10/e p461; KDT 6/e p426)
Friends, this seems to be another blunder from paper-setter. According to us, the question should contain ‘EXCEPT’ in the
stem.
Three drugs given in the options i.e. clozapine, fluphenazine and paroxetine have anti-cholinergic properties and should
be avoided in angle closure glaucoma. Therefore, if the question was correctly framed as ‘all should be avoided in glaucoma
except’, the answer would have been pilocarpine.
But, if we have to choose the answer for the question as such, we will go with clozapine, as it has maximum anti-cholinergic
properties.
11. Ans. (c) Cholinergic (Ref: Katzung 10/e p76; KDT 6/e p93)
• Autonomic ganglia (both sympathetic as well as parasympathetic) release ACh that stimulates the N N
nicotinic
receptors on the post-ganglionic fibres.
12. Ans. (b) VI (Ref: Katzung 10/e p75; KDT 6/e p89)
• Parasympathetic system is craniosacral in outflow. Cranial part involves III (oculomotor), VII (facial), IX (glossopharyngeal)
and X (vagus) nerves whereas sacral portion includes S2 to S4.
13. Ans. (b) Nor-adrenaline (Ref: Katzung 10/e p76; KDT 6/e p116)
• Neurotransmitter secreted at end organ effectors of sympathetic system is mostly nor-adrenaline (except in sweat
glands and hair follicle, where it is acetylcholine) whereas it is acetyl-choline at parasympathetic system.
14. Ans. (d) Metoprolol (Ref: Katzung 10/e p103, 152; KDT 6/e p144-147)
• Metoprolol is a beta blocker with local anaesthetic activity. Such beta blockers are not indicated in glaucoma.
• Apraclonidine (alpha 2 agonist), timolol (beta blocker without local anaesthetic activity) and pilocarpine (directly
acting miotic) are used in glaucoma.
15. Ans. (b) Brimonidine (Ref: Goodman & Gilman 12/e p1788; KDT 6/e p146-147)
• Apraclonidine and brimonidine can cross blood brain barrier and may result in CNS depression and apnea in
neonates. These are therefore contra-indicated in children less than 2 years.
16. Ans. (d) Reactivation of AChE enzyme (Ref: Katzung 10/e p116; KDT 6/e p105)
• Pralidoxime and diacetylmonoxime are cholinesterase regenerator compounds used for organophosphate poisoning.
17. Ans. (a) Edrophonium (Ref: KDT 6/e p104)
Myasthenia gravis can be differentiated from cholinergic crisis with the help of a short acting anticholinesterase agent,
edrophonium. It improves the symptoms in myasthenia gravis whereas worsens the condition in cases of cholinergic crisis.
Neostigmine is used for the treatment of myasthenia.
18. Ans. (a) Hemicholinium prevents the release of acetylcholine from the storage vesicles; (b) Botulinum toxin increase
the ACh release; (d) Vesamicol inhibit the uptake of choline (Ref: KDT 6/e p94)
Autonomic General Pharmacology
Nervous System
• Hemicholinium blocks choline uptake (the rate limiting step in ACh synthesis).
• Vesamicol block the transport of ACh into the synaptic vesicles.
• Botulinum toxin inhibits the release of acetylcholine.
• Acetylcholine esterase is inhibited by organophosphates and carbamates.
• Pralidoxime reactives ACh.
19. Ans. (a) It is a quarternary ammonium compound; (e) It possess agonistic action on N M
receptors (Ref: KDT 6/e p101-102;
Lee 12/e p217)
• Neostigmine is a reversible cholinesterase inhibitor. It is a quarternary ammonium compound. (lipid insoluble agent),
so it does not cross blood-brain-barrier.
• It is partly hydrolyzed by serum cholinesterase and partly excreted unchanged by the kidneys.
• It possesses some agonistic action on N M
receptors.
20. Ans. (b) Rise in blood pressure (Ref: KDT 6/e p97)
Stimulation of muscarinic (M 3
) receptors decreases BP whereas parasympathetic system stimulation has no effect on BP
because blood vessels contain M 3
receptors but no parasympathetic supply.
21. Ans. (d) Cycloplegia (Ref: KDT 6/e p97)
Pilocarpine is a directly acting cholinergic drug. It causes miosis and cyclospasm (not cycloplegia). It can increase all secretions
of the body.
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