MCQs-Drugs Acting on Peripheral (Somatic) Nervous System part 1 I Pharmacology KD Tripathi mcqs part 23

 


23.1 Which of the following drugs is a nondepolarizing neuromuscular blocker:

A. Succinylcholine

B. Vecuronium

C. Decamethonium

D. Dantrolene sodium


23.2 The site of action of d-tubocurarine is:

A. Spinal internuncial neurone

B. Motor nerve ending

C. Muscle end-plate

D. Sodium channels in the muscle fibre


23.3 At the muscle end-plate, d-tubocurarine reduces the:

A. Number of Na+ channels

B. Duration for which the Na+ channels remain open

C. Ion conductance of the open Na+ channel

D. Frequency of Na+ channel opening


23.4 Depolarizing neuromuscular blockers differ from competitive

blockers in the following attributes except:

A. They induce contraction of isolated frog rectus abdominis muscle

B. Ether anaesthesia intensifies block produced by them

C. Tetanic nerve stimulation during partial

depolarizing block produces well sustained

contraction

D. Neostigmine does not reverse block produced by them 


23.5 Succinylcholine produces spastic paralysis in:

A. Rabbits

B. Frogs

C. Birds

D. Patients with atypical pseudocholinesterase


23.6 The fall in blood pressure caused by d-tubocurarine is due to:

A. Reduced venous return

B. Ganglionic blockade

C. Histamine release

D. All of the above


23.7 Select the skeletal muscle relaxant that is commonly

used for endotracheal intubation despite causing

histamine release, K+ efflux from muscles and

cardiovascular changes:

A. Pipecuroniun

B. Succinylcholine

C. Pancuronium

D. Cisatracurium 


23.8 Neuromuscular blocking drugs do not produce central actions because:

A. They do not cross the blood-brain barrier

B. Nicotinic receptors are not present in the brain

C. They are sequestrated in the periphery by tight binding to the skeletal muscles

D. They do not ionise at the brain pH 


23.9 Pancuronium differs from tubocurarine in that:

A. It is a depolarizing blocker

B. Its action is not reversed by neostigmine

C. It can cause rise in BP on rapid I.V. injection

D. It causes marked histamine release 


23.10 Which of the following drugs undergoes ‘Hofmann’ elimination:

A. Succinylcholine

B. Pancuronium

C. Vecuronium

D. Atracurium


23.11 The neuromuscular blocker that does not need

reversal of action by neostigmine at the end of the

operation is:

A. d-Tubocurarine

B. Doxacurium

C. Pipecuronium

D. Mivacurium 


23.12 The most rapidly acting nondepolarizing neuromuscular

blocking agent which can be used as an alternative

to succinylcholine for tracheal intubation is:

A. Rocuronium

B. Pancuronium

C. Doxacurium

D. Pipecuronium 


23.13 Succinylcholine is the preferred muscle relaxant for tracheal intubation because:

A. It produces rapid and complete paralysis of respiratory muscles with quick recovery

B. It does not alter heart rate or blood pressure

C. It does not cause histamine release

D. It does not produce postoperative muscle soreness


23.14 Which of the following is applicable to mivacurium:

A. It undergoes Hoffmann elimination

B. It is the shortest acting nondepolarizing neuromuscular blocker

C. It is excreted unchanged by kidney

D. It does not cause histamine release


23.15 Neostigmine reverses the following actions of d-tubocurarine except:

A. Motor weakness

B. Ganglionic blockade

C. Histamine release

D. Respiratory paralysis


23.16 Postoperative muscle soreness may be a side effect of the following neuromuscular blocker:

A. d-tubocurarine

B. Succinylcholine

C. Pancuronium

D. Atracurium 


23.17 The following antibiotic accentuates the nuromuscular blockade produced by pancuronium:

A. Streptomycin

B. Erythromycin

C. Penicillin G

D. Chloramphenicol 


23.18 Dantrolene sodium reduces skeletal muscle tone by:

A. Reducing acetylcholine release from motor nerve endings

B. Suppressing spinal polysynaptic reflexes

C. Inhibiting the generation of muscle action potential

D. Reducing Ca2+ release from sarcoplasmic reticulum in the muscle fibre 


23.19 Which of the following is a centrally acting skeletal muscle relaxant:

A. Carisoprodol

B. Dantrolene sodium

C. Quinine

D. Decamethonium 


23.20 Select the muscle relaxant that is used to control

spasticity associated with upper motor neurone

paralysis:

A. Vecuronium

B. Succinylcholine

C. Chlorzoxazone

D. Baclofen 


23.21 The GABAB receptor:

A. Is an intrinsic ion channel containing receptor

B. Mediates neuronal depolarization

C. Is insensitive to blockade by bicuculline

D. Regulates intracellular cAMP 


23.22 The following is a skeletal muscle relaxant that acts

as a central α2 adrenergic agonist:

A. Tizanidine

B. Brimonidine

C. Chlormezanone

D. Quinine


23.23 Which of the following is not true of tizanidine:

A. It is a clonidine congener used in spasticity

due to stroke or spinal injury

B. It reduces muscle tone by activating GABAB receptors

C. It inhibits release of excitatory amino-acids in spinal interneurones

D. It reduces muscle spasms without producing weakness


23.24 Diazepam is used as a muscle relaxant for:

A. Deep intra-abdominal operation

B. Tracheal intubation

C. Tetanus

D. Diagnosis of myasthenia gravis 


23.25 Indications of centrally acting muscle relaxants

include all of the following except:

A. Balanced anaesthesia

B. Traumatic muscle spasms

C. Torticollis

D. Electroconvulsive therapy


Ans:

23.1 B 23.2 C 23.3D 23.4 B 23.5 C 23.6 D 23.7 B 23.8 A 23.9 C 23.10D 23.11D 23.12 A 23.13 A 23.14 B 23.15 C 23.16 B 23.17 A 23.18D 23.19 A 23.20D 23.21 C 23.22A 23.23 B 23.24 C 23.25 A 

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