Paper I
Question
(
- (a) Classify drugs used for treatment of epilepsy with two examples each. ( 6 mark(s)
- (b) Write the mechanism of action, uses and adverse effects of sodium valproate. ( 4 mark(s)
- (c) Outline the management of status epilepticus. 5 mark(s)
Answer
a) Classification of antiepileptic drugs, two examples each
| Mechanism | Examples |
|---|---|
| Na⁺ channel blockers | Phenytoin, Carbamazepine |
| Ca²⁺ channel blockers (T-type) | Ethosuximide, Valproate |
| GABA-potentiating agents | Diazepam, Phenobarbitone |
| Newer/multiple mechanisms | Levetiracetam, Topiramate |
b) Sodium valproate — mechanism, uses, adverse effects Mechanism: increases GABA levels (inhibits GABA transaminase), blocks voltage-gated Na⁺ channels, and blocks T-type Ca²⁺ channels — a triple mechanism underlying its broad-spectrum efficacy. Uses: generalized tonic-clonic seizures, absence seizures, myoclonic seizures, bipolar disorder, migraine prophylaxis. Adverse effects: hepatotoxicity, teratogenicity (highest neural tube defect risk among antiepileptics), weight gain, tremor, alopecia, thrombocytopenia.
c) Management of status epilepticus
- Airway, breathing, circulation; oxygen; IV access; check and correct blood glucose.
- First-line: IV Lorazepam or Diazepam.
- If seizures continue: IV Phenytoin/Fosphenytoin loading dose.
- Refractory status: IV Valproate or Levetiracetam; if still refractory, general anesthesia (Midazolam/Propofol/Thiopental infusion) with continuous EEG monitoring and ICU care.