Lacosamide, new antiepileptic with broad perspectives

Sir,

Lacosamide is a third-generation antiepileptic drug (AED) with a good pharmacokinetic and pharmacodynamic profile that has been recently approved as adjuvant therapy in difficult-to-control partial seizures, with or without secondary generalisation.¹ Its main application is in adjuvant therapy for refractory partial seizures² with a dual mechanism of action: inactivation of slow sodium channels and modulation of response to type 2 collapsin.^1,2

We present our experience with lacosamide in various epileptic and non-epileptic disorders in which we observed a favourable response.

We present a 48-year-old female patient suffering migraine without aura from the time she was 18 (2–4 headaches/month) and no other relevant history. She referred episodes of distorted vision followed by generalised seizure crises from age 20. She was following treatment with 200 mg carbamazepine every 8 h and 3000 mg levetiracetam, and was well controlled (1 crisis of distorted vision lasting various seconds per week). Neurological examination and neuroimaging were normal. The EEG showed focality of sharp waves in the right parietal area. The patient was diagnosed with partial seizures consisting of secondarily generalised metamorphopsia. She presented leucopoenia secondary to carbamazepine, so this was changed to 100 mg lacosamide every 12 h; leukocytes returned to normal after the change. After 4 months without any seizures, the patient reported that she had not suffered any migraine headaches since she had started taking lacosamide.

Additionally, we present two cases of epilepsy that were difficult to control with drugs. Both followed multiple therapies in various combinations: the first case, with a frequency of 6 crises per month, was taking carbamazepine. This was replaced by lacosamide due to the presence of secondary hyponatraemia. The crises decreased to 2/month and sodium values returned to normal. The second case, with multifocal crises, followed treatment with 5 AEDs. After being admitted in a convulsive state, 3 drugs were stopped and lacosamide was started. A rapid control of seizures was achieved. After 5 months, the patient maintained this improvement, with 2 crises per month.

We present a fourth case of complex partial seizures in a patient who was being treated with oxcarbazepine, which was changed to lacosamide due to secondary hyponatraemia. The crises disappeared and natraemia returned to normal.

In Spain, there are very few case reports on experience with lacosamide after it was commercialised. It was used in these 4 patients in different situations: metamorphopsia, status epilepticus, complex partial seizures and drug-resistant epilepsy, highlighting its effectiveness in a case of migraine, of which there are no cases reported in the current literature. Known results were confirmed, but we also observed an adequate response in situations not yet listed. The case with migraine suggests that lacosamide may come to have a role as a neuromodulator.

Clearly, controlled studies are needed to demonstrate the efficacy of lacosamide in the prevention of migraine. However, positive results such as the ones described above are preliminary findings that support this drug as an alternative in this indication in the future, especially if we consider that it can be effective and well tolerated. It is important to note the limited potential for lacosamide interactions, as well as the few side effects described with its use, generally mild and transient, and dose-dependent or unspecific.^1–5

These observations, along with the known risk-benefit profile of lacosamide, suggest that it may be safe and effective in the treatment of not only epilepsy, but also for migraines.