Koufman writes about taking two drugs:
Treatment Side Bar: Amitriptyline and gabapentin seem to work together better that either does separately. Some (few) patients do well an amitriptyline alone, but more often than not, I recommend a small dose of amitriptyline while slowly titrating the gabapentin up to an effective dose.
https://jamiekoufman.com/the-vagus-nerve-part-ii-what-happens-when-it-goes-bad-vagally-mediated-voice-symptoms-and-neurogenic-pain-syndromes/