Switching from traditional sodium channel blockers to lacosamide in patients with epilepsy

Lacosamide (LCM) is a recently developed sodium channel blocker (SCB), which acts mainly on the slow activation state in sodium channels. Although LCM shares a range of dose-dependent adverse effects with traditional SCBs, it has several advantages in that it does not induce hepatic drug metabolizing enzymes and has less risk of drug interactions and idiosyncratic adverse effects.

We retrospectively analyzed the efficacy and tolerability of switching from traditional SCBs to LCM. The reason for the switch was classified as insufficient efficacy, adverse effects, or concern about metabolic derangement, resulting in conditions such as atherosclerosis and osteoporosis, with long-term use of traditional SCBs.

Seventy-five patients were switched to LCM from traditional SCBs. The overall rate of successful switching was high (81.3%, 61/75 patients). However, the success rate was strongly dependent on the reason for the switch; patients with insufficient efficacy on SCBs had less chance of a successful switch (71.8%, 28/39 patients) than those with adverse effects (89.5%, 17/19) or concerns about metabolic derangement (94.1%, 16/17, p =  0.038). Patients with insufficient efficacy were significantly younger (p =  0.004) and had a higher chance of drug-resistant epilepsy (p =  0.004) than those in the other two groups.

Our study shows that switching from traditional SCBs to LCM is usually successful and the likelihood of a successful switch is higher in patients when the reason for the switch is adverse effects or concerns about metabolic derangement on traditional SCBs.