lamotrigine + valproate

Lamotrigine + valproate is a combination therapy used primarily in the management of epilepsy, particularly for patients with medically refractory epilepsy. Lamotrigine is a triazine derivative antiepileptic drug that inhibits voltage-sensitive sodium channels, stabilizing neuronal membranes and suppressing the release of excitatory neurotransmitters such as glutamate and aspartate. It may also block L-, N-, and P-type calcium channels and weakly inhibit serotonin 5-HT3 receptors[6]. Valproate (valproic acid or its sodium salt) acts mainly by increasing brain concentrations of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter, through multiple mechanisms including inhibition of GABA transaminase. When combined, these drugs have synergistic effects but also significant pharmacokinetic interactions; notably, valproate inhibits the glucuronidation metabolism of lamotrigine via UDP-glucuronosyltransferases, leading to increased plasma levels and risk of toxicity for lamotrigine[2][4][5]. This necessitates careful dose adjustment—typically reducing the dose of lamotrigine by at least 50% when co-administered with valproate[5]. The combination is approved for use in epilepsy management when monotherapy is insufficient.

Brand names

LamictalDepakote

Other names

lamotrigine + valproic acidlamotrigine + valproate sodium