Paper I
2014 March (2010 Scheme) · 40 marks · 120 min

Question

A 28 years old man, while working on his computer in an IT company, suddenly went blank, fell down and appeared to be unconscious. He regains consciousness in the next 5 minutes but was confused and could not remember what happened. When he consulted a neurologist, he was diagnosed to have absence seizures. Answer the following:

  • (a) Name two drugs useful in absence seizures 1 mark(s)
  • (b) Explain the mechanism of action of phenytoin 2 mark(s)
  • (c) List four uses of carbamazepine 2 mark(s)
  • (d) Mention two drugs used in status epilepticus 1 mark(s)
Q16 marksEssays

Answer

(a) Drugs useful in absence seizures

  • Sodium valproate
  • Ethosuximide

(b) Mechanism of action of phenytoin

  • Blocks voltage-gated sodium channels, preferentially binding to and prolonging their inactivated state
  • This use-dependent blockade reduces sustained high-frequency repetitive firing of neurons, limiting the spread of seizure activity, without affecting normal neuronal transmission

(c) Uses of carbamazepine

  • Partial (focal) and generalized tonic-clonic seizures
  • Trigeminal neuralgia
  • Bipolar disorder (mood stabilizer)
  • Central diabetes insipidus

(d) Drugs used in status epilepticus

  • Diazepam / Lorazepam (IV)
  • Phenytoin / Fosphenytoin (IV)

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