Positive effect of drug on nerve pain condition

Anti-epileptic drug also has effect on small fibre neuropathy

Researchers at Maastricht UMC+ have shown that the drug lacosamide has a positive effect on patients with small fibre neuropathy – a condition in which people suffer continuous pain. The drug reduces pain, ensures better sleep and has a positive influence on patients' general wellbeing. The results were published recently in the scientific journal Brain. In addition, Bianca de Greef gained her PhD with research on the nerve condition.

Small fibre neuropathy is characterised by continuous burning or prickling pain. However, the sensation can vary from one patient to another and can also manifest itself in other ways. The pain is the result of the small peripheral nerve fibres failing to function properly. Causes range from a hereditary defect to diabetes, or it can be a side effect of chemotherapy. However, there is as yet no effective treatment for the condition, which annually affects 450 people who come to Maastricht University Medical Center.

Overactive
Maastricht researchers showed in previous studies that the pain is connected with overactivity of sodium channels in the nerve cells. In a 'normal' pain sensation, the channels become active in order to send the 'pain' signal to the brain. But in patients with small fibre neuropathy, this signal is constant, resulting in persistent pain. The researchers thought that blocking the overactive channels could be the key to successfully dealing with the condition. Lacosamide is a drug which is normally used to treat epilepsy and which has exactly that blocking effect.

Positive effect
In the study, 24 patients with a hereditary form of small fibre neuropathy were divided into two groups and were treated for eight weeks. One group began by taking lacosamide, then later took a placebo (a pill containing no active substance). In the other group, the process was reversed. The pain was reduced in nearly 60 per cent of the patients who were taking the drug (21 per cent with the placebo). In addition, a third of the patients reported that their general feeling of wellbeing had improved (only 4 per cent with the placebo). Patients taking the drug also slept better.

Other patients could benefit
Although the drug was tested on a specific group of patients with an inherited form of small fibre neuropathy, researchers expect that other groups could also benefit. "After all, something is wrong with the sodium channels of all these patients," says De Greef. "Lacosamide specifically has an effect on this. Therefore, we could expect the drug to have a positive effect in other patients, too, but we still have to find that out."

The study of the effect of lacosamide on small fibre neuropathy was made possible by support from the Princess Beatrix Muscle Fund [Prinses Beatrix Spierfonds].