Offering a glimmer of hope for people suffering from chronic nerve pains, researchers have found that a novel substance inhibits the pain effectively and is well tolerated.

The standard treatment for this chronic nerve pain, known as trigeminal neuralgia, a condition that can lead to acute pain in the teeth or facial area, is associated with burdening side effects. In this study, published in the journal Lancet Neurology, the substance, BIIB074, was found to reduce the pain to a tolerable level.

"Unlike conventional drugs, which often cause tiredness and concentration problems, BIIB074 was not only effective, but also very well tolerated," said one of the researchers, Dominik Ettlin, a dental specialist at University of Zurich in Switzerland.

"We will now test the new substance in a lot more subjects during the next study phase, which will reveal whether the new hope for more effective pain relief is justified," he added. Bouts of pain in people with trigeminal neuralgia can be triggered by touch, such as shaving, putting on make-up, showering, talking and tooth brushing, or even a gust of wind. The cause is usually an irritation of the trigeminal nerve, the cranial nerve responsible for the sensory innervation of the facial area, parts of the scalp, and the oral cavity.

Pain signals reach the brain via the activation of sodium channels located in the membranes of nerve cells. The sodium channel "1.7" is frequently expressed on pain-conducting nerves and higher pain intensity is linked to higher channel activity. Blocking this sodium channel inhibits the pain. In trigeminal neuralgia, the nerve damage is presumed to be at the base of the skull. However, this region is hard to reach by local injections and therefore requires drug treatment. In this study, the researchers found that the more active this sodium channel gets, the stronger it is blocked by the novel substance BIIB074. By contrast, currently available medications block the sodium channel irrespective of the nerve activity, which commonly results in burdening side effects, the study said.