811.Which is false about local anaesthetics
A.They produce nerve conduction block by decreasing permeability to Na+
B.They are active in cationic form
C.In high doses theymay produce prolongation of the PR interval on ECG
D.They only effect the transmission of action potentials in peripheral nerves
E.Hypersensitivity is more likely with the ester class than the amine class

812.Which is false with respect to propofol
A.It is excreted unchanged in the urine
B.It is tolerated better than thiopentone
C.It causes marked decrease in BP
D.It may cause pain at the site of injection
E.It may cause apnoea

813.Regarding inhaled anaesthetics
A.The concentration of an individual gas in a mixture is inverselyproportional to its partial pressure
B.The blood gas partition co-efficient of N2O is about 0.5
C.The rate of rise of anaesthetic gas tension in arterial blood does not depend on minute alveolar ventilation
D.They have no effect on right atrial pressure or contractility of the heart
E.N2O us probably the only inhaled anaesthetic that causes a decrease in tidal volume and an increase in RR

814.The GABA receptor
A.Is a Na+channel
B.Requires a γ-2 subunit to be sensitive to benzodiazepines
C.Is unaffected by thiopentone
D.Is a single transmembrane protein
E.Is only present in the cerebral cortex

815.Phenytoin
A.Blocks Na channels and inhibits the generation of repetitive action potentials
B.Does not bind to plasma proteins
C.Is excreted in bile
D.In high does obeys 1storder metabolism
E.Does not affect carbamazepine levels

816.With regard to anticonvulsants in general which is false
A.They are cleared mainly by hepatic mechanisms
B.They have low extraction ratios
C.The increase in percentage of free drug causes reduction in total drug concentration
D.Elimination is mainly by zero order except phenytoin
E.They tend to have short half lives that are less than 12 hours

817.Which anticonvulsant can cause hepatotoxicity
A.Carbamazepine
B.Dilantin
C.Diazepam
D.Sodium valproate
E.Ethosuximide

818.Suxamethonium
A.Is antagonized by neostigmine
B.May induce hyperkalaemia
C.Is a non-depolarising muscle relaxant
D.Is contraindicated within 12 hours of a burn injury
E.May cause a severe tachycardia if the dosage isrepeated

819.Which neuromuscular blocker is most likely to induce tachycardia
A.Atracurium
B.Vecuronium
C.Pancuronium
D.Succinylcholine
E.Rocuronium

820.The duration of Suxamethoniumis
A.30 secs
B.2 mins
C.4 mins
D.10 mins
E.30 mins

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