Botulinum toxin-type A: could it be an effective treatment option in intractable trigeminal neuralgia?

Abstract

Botulinum toxin type A (BTX-A) has been reported to have analgesic effects independent of its action on muscle tone, mostly by acting on neurogenic inflammatory mediators and controlling the neurotransmitter release of sensory and autonomic nerve terminals that are involved in many chronic painful conditions as chronic intractable trigeminal neuralgia (TN).The aim of our work was evaluating the efficacy, safety, and tolerability of BTX-A for the treatment of intractable idiopathic TN. This was a randomized, single-blinded, placebo-control study carried out on 20 Egyptian patients with intractable TN. Patients received a one-time subcutaneous administration of BTX-A using "follow the pain" method. The primary efficacy measure was reduction in pain severity on the 10-cm VAS score as well as in paroxysms frequency from the baseline to week 12 (endpoint last observation carried forward [LOCF]). Secondary efficacy measures included QoL assessment and number of acute medications received from baseline to the endpoint. Pain reduction at the 12-week endpoint was significant in BTX-A group (p<0.0001); VAS scores at endpoint LOCF relative to baseline for BTX-A group showed a decrease of 6.5 compared with a decrease of 0.3 for placebo, also there was a significant decrease in the number of acute medications and an increase in QoL functioning scale. These results indicate that BTX-A has a direct analgesic effect in patients with TN and can represent a therapeutic option for intractable cases.