Ocular FIP treatment moves toward clearer dosing guidance
CURRENT BRIEF VERSION: A new VetGirl podcast is spotlighting a fast-moving area in feline medicine: how clinicians are approaching ocular feline infectious peritonitis, or FIP, in the antiviral era. The discussion comes as published evidence continues to build around remdesivir and GS-441524 for cats with ocular involvement, including a 2025 observational case series that tracked 20 cats with FIP-associated ocular disease treated with remdesivir, GS-441524, or both. In that report, most cats started on injectable remdesivir and many received 15-20 mg/kg dosing, reflecting the higher-dose strategies commonly used when ocular signs are present. The podcast also underscores why these cases matter clinically: ocular disease is seen much more often in non-effusive FIP than effusive disease, and signs can include anterior uveitis, keratic precipitates, iris color change, dyscoria, hyphema, hypopyon, retinal lesions, hemorrhage, detachment, or perivascular cuffing. Separately, the Feline Veterinary Medical Association’s 2025 FIP update guide recommends oral GS-441524 at 20 mg/kg once daily, or split every 12 hours, for cats with ocular signs. In the U.S., this conversation is also shaped by the FDA’s May 10, 2024 announcement that it does not intend to enforce approval requirements for patient-specific compounded GS-441524 prescribed by veterinarians for FIP under outlined conditions, even though these compounded products remain unapproved drugs. (pmc.ncbi.nlm.nih.gov)
Why it matters: For veterinary professionals, ocular FIP is no longer a fringe or purely anecdotal treatment space. The newer literature suggests ocular cases can respond well, but they often require different dosing assumptions than non-ocular disease, in part because the eye is one of the harder tissues to penetrate. Broader FIP education is also shifting toward more practical treatment refinement, including whether higher induction dosing, biomarker trends such as serum amyloid A, alpha-1 acid glycoprotein, and albumin:globulin ratio, and clearer stop criteria can help guide duration and reduce unnecessary cost. Treatment decisions still sit within a complicated regulatory and compounding landscape, making case selection, client communication, monitoring, and pharmacy sourcing especially important for general practitioners and feline-focused teams. (pmc.ncbi.nlm.nih.gov)
What to watch: Expect more attention on standardized dosing, duration, relapse management, objective treatment-stop criteria, and how legally compounded antivirals perform in real-world ocular and neurologic FIP cases. Broader FIP discussions are also emphasizing practical diagnosis, since many cats are still managed on a presumptive rather than definitive basis. (catvets.com)