Elimination kinetics of nonsteroidal anti-inflammatory drugs during carbon hemoperfusion in 19 dogs with toxicosis

Abstract Objective To describe the elimination kinetics of NSAIDs during carbon hemoperfusion (cHP) in dogs with toxicosis, specifically the apparent elimination rate constant, half-life, and plasma reduction. Methods 19 client-owned dogs (median age, 2.5 years; median body weight, 22 kg) with ibuprofen (n = 10), carprofen (5), or naproxen (4) toxicosis treated with cHP at 2 academic veterinary teaching hospitals from November 30, 2022, through July 7, 2024. Dogs were presented after known or suspected ingestion at median estimated maximum doses of 720, 200, and 325 mg/kg for ibuprofen, carprofen, and naproxen, respectively. The median interval from ingestion to cHP was 6.8 hours. Plasma concentrations were measured by LC-MS-MS in-serial samples collected during and, when available, after cHP. Results The median total plasma reduction was 58% (IQR, 51 to 80). The overall half-life during cHP was 1.3 hours (IQR, 1.1 to 1.8) by the 2-point method, concordant by regression (1.4 hours), and approximately 3.7-, 5.4-, and 52.0-fold shorter than respective therapeutic-dose half-lives. Among 5 dogs with posttreatment samples, plasma concentration rebounded after cHP in 1 naproxen-treated dog. The cHP-associated rate constant exceeded the intrinsic rate constant 11- to 40-fold in 4 of 5 dogs. Conclusions Carbon hemoperfusion was associated with substantial reductions in plasma NSAID concentrations during treatment in dogs with severe ibuprofen, carprofen, or naproxen toxicosis. Most of the decline occurred early in the session. Further studies are warranted to optimize treatment protocols. Clinical Relevance Carbon hemoperfusion markedly shortened NSAID elimination half-lives in dogs with severe toxicosis, accelerating removal well beyond endogenous elimination.