Name: Lamotrigine (Lamictal)
Class: Antiepileptic Agent (Complex-Partial)
Mechanism: Inhib. release of glutamate. Inhib Na+-med. sustained firing.
Absorption: Oral ® 100% bioavailability.
Dist.: Protein binding 55%
Metabolism.: Primarily hepatic Metabolism.
Excretion, t½: Long t½.
Toxicity/S.E.s: Most common—somnolence, dizziness, headache, blurred vision, diplopia, ataxia, n/v. Less common—rash (mild-severe), esp. w/concurrent use of valproic acid. Drug interactions—¯ w/phenytoin, carbamazepine; w/valproic acid. \ When administering w/valproic acid, start w/low dose (25 mg/d), then titrate up.
Utility: Adj. therapy of partial seizures, including secondarily generalized. Possible alt. for generalized absence.
Special Features: Long t½, low toxicity profile, defined therapeutic range, different Mechanism of action. But Metabolism. affected by concurrent antiepileptic therapy, and experience w/monotherapy is limited.