PNS Drugs MCQs

1. 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

ANSWER:  [  c  ]

2. Which of the following drugs undergoes ‘Hofmann’ elimination

A. Succinylcholine

B. Pancuronium

C. Vecuronium

D. Atracurium

ANSWER:  [  d  ]

3. 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

ANSWER:  [  d  ]

4. 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

ANSWER:  [  a  ]

5. Which of the following drugs is a nondepolarizing neuromuscular blocker

A. Succinylcholine

B. Vecuronium

C. Decamethonium

D. Dantrolene sodium

ANSWER:  [  b  ]

6. 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

ANSWER:  [  c  ]

7. 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

ANSWER:  [  d  ]

8. 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

ANSWER:  [  b  ]

9. Succinylcholine produces spastic paralysis in

A. Rabbits

B. Frogs

C. Birds

D. Patients with atypical pseudocholinesterase

ANSWER:  [  c  ]

10.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

ANSWER:  [  d  ]

11. Select the skeletal muscle relaxant that is commonly used for endotracheal intubation despite causing histamine release, K+ efflux from muscles and cardiovascular changes

A. Pipecuronium

B. Succinylcholine

C. Pancuronium

D. Cisatracurium

ANSWER:  [  b  ]

12. 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

ANSWER:  [  a  ]