Pharmacological inhibition of NaV1.8 by suzetrigine reveals potent analgesic potential without tolerance development in mice

The Voltage-gated sodium channel NaV1.8 is a critical determinant of nociceptive signaling in primary sensory neurons. Here, we evaluated the analgesic potential of suzetrigine, a potent clinically approved NaV1.8 blocker, using electrophysiological, behavioral, and tolerance paradigms in mice. Whole-cell recordings from dorsal root ganglion neurons revealed that suzetrigine inhibited tetrodotoxin (TTX)-resistant sodium currents in a concentration-dependent manner (IC₅₀ = 0.35 ± 0.17 μM), consistent with high-affinity NaV1.8 inhibition. In vivo, intraperitoneal administration of suzetrigine significantly reduced nocifensive behaviors in the formalin test, attenuated CFA-induced thermal hypersensitivity, and reversed mechanical hyperalgesia in the partial sciatic nerve injury-induced neuropathy model. Importantly, repeated dosing did not produce tolerance in a chronic administration paradigm. Although suzetrigine showed limited efficacy in clinical trials for neuropathic pain, its robust analgesic effects in mouse models underscore the challenges of translating preclinical findings to human neuropathic pain, while still supporting the potential of NaV1.8-targeted therapies.