UKMLA PLAB AMC USMLE Prometric MCQ

Question:
A 55yr old presented with sharp pain on the left side of the face. It was associated with flinching on the face precipitated by eating. The patient was diagnosed to be suffering from trigeminal neuralgia.
The drug of choice for the treatment of trigeminal neuralgia is

a) Indomethacin
b) Sodium valproate
c) Carbamazepine
d) Phenobarbitone
e) Colchicine

 
Correct Answer: C

Explanation:

Trigeminal neuralgia is a disorder characterized by severe pain along the second and third divisions of the trigeminal nerve. The severe pain causes the patient to flinch on the face and the pain is usually precipitated by eating. The etiology of the pain is not exactly known but the current hypothesis suggests that the pain is due to the compression of the nerve rootlets at their entry to the brain stem by aberrant loops of the cerebellar arteries.  Carbamazepine is basically an anti-epileptic drug but it is the drug of choice used for the treatment of Trigeminal neuralgia. The drug is highly effective in reducing the pain. Exact mechanism for the antineuralgic action is unknown; may involve gamma-aminobutyric acid (GABAB) receptors, which may be linked to calcium channels.  Indomethacin is a very potent non-steroidal anti-inflammatory drug but it is of no use in trigeminal neuralgia.  Phenobarbitone & sodium valproate are also anti-epileptic drugs but they are not useful in the treatment of trigeminal neuralgia.  Colchicine is the drug used for pain relief in gouty arthritis and has no role in trigeminal neuralgia.