A 25yr old women with myoclonic seizures is well controlled on valproate. she indicates that she is intrested in conceiving in next year. With respect to her antiepileptic medication, wof should be considered
High-Yield Explanation
Lamotrigine Mech of action:- Lamotrigine is a broad-spectrum antiepileptic. It modifies maximal electric shock and decreases electrically evoked as well as photic after-discharge duration. Prolongation of Na+ channel inactivation and suppression of high frequency firing has been demonstrated. In addition, it may directly block voltage sensitive Na+ channels, thus stabilizing the presynaptic membrane and preventing release of excitatory neurotransmitters, mainly glutamate and aspaate. This may account for its broader-spectrum of antiseizure efficacy. uses:- Absence and myoclonic or akinetic epi-lepsy cases have also been successfully treated. Reduction in seizure frequency or complete control is obtained as frequently as with carbamazepine. Pharmacokinetics:- Lamotrigine is well absorbed orally and metabolized completely in liver. Its t 1/2 is 24 hr, but is reduced to ~16 hr in patients receiving phenytoin, carbamazepine or phenobarbitone. On the contrary valproate inhibits glucuronidation of lamotrigine and doubles its blood level, but valproate levels are lowered by lamotrigine. Reduce the dose of lamotrigine to half in patients taking valproate. However, metabolism of other anticonvulsants and oral contraceptives is not altered. Ref:- kd tripathi;pg num:-419