Long term efficacy and safety of onabotulinumtoxin a as monotherapy in intractable trigeminal neuralgia

Abstract

Trigeminal neuralgia(TN) is one of the most agonizing facial pain disorders that humans endure. Studies on onabotulinumtoxin A(BTX-A) treatment for TN are limited, but promising with respect to TN of no identifiable cause. However, more clinical data on the risk-benefit profile for long term treatment beyond one year is needed. We aimed to investigate the efficiency and safety of BTX-A treatment in a 65-year-old male without previous disease who in July 2012 presented with TN. The patient was medically treatment refractory due to insufficient pain relief and adverse events of drowsiness. No definite neurovascular compression was notified in brain MRI and surgery was not considered. BTX-A was injected into the pain trigger zones of the trigeminal nerve with the follow the pain injection paradigm. Complete analgesia was reported 2 weeks after BTX-A injection. Pain medications were discontinued. Regular BTX-A treatment every 12 weeks during the next 33 months showed sustained analgesic effect. He showed no severe adverse event except mild difficulty in facial expression. BTX-A has an excellent safety profile and may be efficient for patients with symptomatic TN not suited for conventional therapies. This case provides additional clinical evidence for the consistency of the efficacy and for the long-term safety and tolerability of BTX-A for the pain relief of TN who have been treat with BTX-A every 12 weeks over 33 months (11 treatments) with the follow the pain injection paradigm.