Botulinumtoxin Type-A (BoNTA) in the Management of Refractory Trigeminal Neuralgia: An Expert-Opinion, Practice-Oriented Narrative Review on Behalf of the GRASP Study Group

Trigeminal neuralgia (TN) ranks among the most excruciating neuropathic pain syndromes, characterized clinically by multiple daily episodes of unilateral, paroxysmal, electric shock-like facial pain. The daily activities and quality of life of affected patients are profoundly diminished. First-line pharmacological agents, such as carbamazepine and oxcarbazepine, provide initial relief for many patients. However, a significant proportion eventually develops refractory symptoms or experience intolerable adverse effects, leading to the discontinuation of traditional oral medications. For these patients with complex clinical phenotypes who fail to respond or are intolerant to these therapies, alternative pharmacological strategies are required before considering invasive surgical procedures. Over the past two decades, botulinumtoxin type-A (BoNTA) has become an effective and safe, minimally invasive therapeutic option for refractory TN. This review provides a practical framework for BoNTA use in the clinical setting of refractory TN. To connect the pathophysiological background with clinical patient care, we summarize the current understanding of TN pathophysiology, the proposed mechanisms by which BoNTA exerts its antinociceptive effects and the evolving clinical evidence supporting its efficacy and safety. We also critically examine dosing protocols, injection techniques, long-term outcomes and the integration of BoNTA into the management algorithm of refractory TN.