In Vivo Metabolic Profiling and Elimination Kinetics of Suzetrigine in Dromedary Camels: Implications for Doping Control in Camel Racing

Rationale Suzetrigine (VX‐548, Journavx), the first oral non‐opioid selective NaV1.8 sodium channel blocker approved by the US FDA in January 2025 for acute pain management, was investigated for its in vivo metabolic fate and elimination profile in dromedary camels following oral administration. Methods Urine and plasma samples were collected over a defined postadministration period and analysed by liquid chromatography coupled to high‐resolution mass spectrometry (LC‐HRMS). The relative abundance of each metabolite was tracked across the sampling window to establish elimination kinetics. Results Three metabolites were identified and characterised: two phase I metabolites, M1 ( O ‐demethylation of the methoxyphenyl group) and M2 (monohydroxylation of M1), were detected in urine, while only M1 was observed in plasma. A phase II sulfonate conjugate, M3, was identified exclusively in urine. Compared with the wider metabolite panel from the authors' previously published camel liver study, the in vivo profile was more restricted, reflecting the differences between in vitro biotransformation systems and living biological systems. Conclusion These findings provide the first in vivo metabolic reference data for suzetrigine in camels and establish M1 as the primary candidate marker for routine antidoping screening in this species.