Which statement is true about carbamazepine ?

Used in trigeminal neuralgia Trigeminal neuralgias are characterized by attacks of high intensity electric shock like stabbing pain, set off by even tril stimulation of ceain trigger zones in the mouth or on the face. Carbamazepine is not an analgesic but has a specific action in these neuralgias. It acts by interrupting temporal summation of afferent impulses (by a selective action on high frequency nerve impulses). "Carbamazepine has become the drug of choke for Trigeminal neuralgias". Other antiepileptics such as phenytoin and Baclofen are less efficacious alternatives. More on carbamazepine The most impoant action of carbamazepine is blockade of voltage dependent sodium ion channels, reducing membrane excitability. It is considered the drug of choice for paial seizures Pharamacokinetics Carbamazepine is an extensively metabolized drug. One of the notable propey of carbamazepine is its ability to induce microsomal enzymes (Paso) The t1/2 of carbamazepine decreases from 36 hrs, seen initially, to as sho as 8-12 hrs due to its enzyme inducing propey (it induces its own metabolism). Due to its enzyme inducing propey, carbamazepine effects the metabolism of other drugs too. Toxicity:- The most cocoon dose related adverse effects of carbamazepine are diplopia and ataxia. It may also cause hyponatretnia and water intoxication. One more impoant adverse effect is idiosyncratic blood dyscrasias which may cause aplastic anemia and agranulocytosis.