Meloxicam may induce nephrotoxicity in California sea lions (Zalophus californianus) with chronic domoic acid toxicosis

Objective To describe biochemical and pathologic findings associated with meloxicam-associated nephrotoxicity in California sea lions (CSLs) with concurrent evidence of chronic domoic acid toxicosis. Animals Stranded free-ranging CSLs treated with meloxicam while undergoing rehabilitation in California between 2017 and 2023. Clinical Presentation 6 adult females and 1 male pup were included in this case series due to postmortem evidence of meloxicam-associated nephrotoxicity. Five patients were in treatment for suspected domoic acid toxicosis, and 2 were in treatment for malnutrition. Three individuals showed evidence of antemortem renal impairment (azotemia, electrolyte derangements, and clinical decline), while the other 4 were diagnosed postmortem. Results 6 of the 7 CSLs for which serum was available before and after treatment with meloxicam developed a significant increase in serum creatinine, BUN, phosphorous, and potassium following treatment. At necropsy, renal papillary necrosis was evident on gross and histologic examination consistent with meloxicam-associated nephrotoxicity for all 7 cases. These individuals also had hippocampal atrophy supportive of chronic domoic acid toxicosis. Clinical Relevance This is the first report of meloxicam-associated nephrotoxicity in pinnipeds. While multiple factors such as dehydration, nutrition, other medication, and/or compromised immune function may have contributed to the development of nephrotoxicity, further evaluation of renal effects of domoic acid as well as effects of NSAIDs is warranted in CSLs.