Switching from carbamazepine to lacosamide improved hyponatremia in 6 severely handicapped patients

Abstract

  Objective: Hyponatremia is one of the side effects of carbamazepine (CBZ). Lacosamide (LCM) is a new antiepileptic drug and the same Na＋ channel blocker as CBZ. We examined whether switching to antiepileptic drugs from CBZ to LCM improves hyponatremia in severely handicapped patients. Methods: We retrospectively investigated the patients, admitted to the ward of a severely handicapped patient in National Hospital Organization Shikoku Medical Center for Children and Adults, taking CBZ, loading more than 6.0g of NaCl per day, did not increase their intake of Na and did not have hepatic and renal dysfunction. After performing various tests including serum sodium level, the CBZ was reduced to approximately half the dose, LCM 100mg per day was added at the same time. CBZ was discontinued 14 days later, switched to LCM 200mg, and serum sodium level was evaluated approximately one month later. Results: 6 patients were enrolled, the male-female ratio was 1 : 1, the age was 54.7±4.1 years on average, the serum sodium level before switching was 127.0±1.1mEq/L on average, and the average weight was 35.1±1.7kg. In all cases, serum Na levels were elevated. During the observation period, five patients did not have epileptic seizures, and one case had seizures during switching period, but did not have seizures after switched. LCM switch improved serum Na level from 127.0±1.1mEq/L to 134.5±1.9mEq/L on average (p<0.05). Conclusions: In patients with severe handicap who are suspected to have hyponatremia due to CBZ, switching to LCM can improve hyponatremia.