Evaluation of an indirect NaV1.7 inhibitor as adjunctive analgesic in burn-related neuropathic pain in a cat.

Abstract

Burn-related neuropathic pain (BRNP) can arise following burn-induced nerve damage, affects approximately 6% of burned human patients and can result in chronic pain. Although widely studied in humans, data on BRNP or its treatment in animals is lacking. A 4-year-old domestic shorthair cat was presented with an infected, non-healing wound suspected to be a caustic burn. Initial treatments included surgical debridement, antimicrobials, and corticosteroids, but the cat developed persistent pruritus leading to self-inflicted trauma. Despite various interventions, including prednisone, chloramphenicol and cyclosporine, clinical signs persisted, leading to a referral for suspected BRNP. Additional support for neuropathic pain was provided through thermal sensitivity testing and applying a modified Neuropathic Pain Symptoms Inventory. Treatment with gabapentin, amantadine, and acupuncture yielded little improvement, prompting an increasing escalation in gabapentin dosage. The cat was then treated with gabapentin compounded with compound 194, a small molecule that is a potent and selective inhibitor of voltage-gated sodium channel 1.7 (Na_V1.7). The cat exhibited significant pain relief and improvements in overall condition. After gabapentin was tapered, compound 194 effectively maintained pain control. The cat's clinical condition stabilized with no adverse effects. Hematology and serum biochemistry results remained within reference intervals throughout the treatment period. This case highlights the potential of Na_V1.7 inhibitors in multimodal management of neuropathic pain in animals.