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Kidney Toxicity of GS-441524 in Cats: What We Know

Updated: Mar 25

Feline infectious peritonitis (FIP) is a devastating illness, but thankfully, the groundbreaking antiviral nucleoside analog GS-441524 has offered a lifeline for many cats. However, as a concerned cat owner, you might have heard whispers about its potential impact on kidney function. Let's put these concerns under the microscope.

Evidence of Kidney Toxicity:

  • Transient Elevations in Kidney Enzymes:  Research demonstrates that GS-441524 can sometimes lead to mild, temporary increases in kidney enzyme levels (creatinine, BUN). These usually subside after treatment discontinuation, rarely indicating severe kidney damage. [Supporting Study: Efficacy and safety of the nucleoside analog GS-441524 for treatment of cats with naturally occurring feline infectious peritonitis:]

  • Nephrotoxic at Low Doses in Humans, Rats & Rhesus Monkeys: GS-441524's prodrug, Remdesivir, has shown to be nephrotoxic (kidney toxic) at doses as low as 3mg/kg. Researchers speculate the renal toxicity is due to accumulation of GS-441524, and not Remdesivir itself. (,infections%20in%20humans)

  • Remdesivir vs. GS-441524: the Unanswered Question: In humans, Remdesivir (where GS-441524 is the active metabolite) has shown some association with kidney toxicity.  The specific contribution of GS-441524, versus other inactive ingredients in Remdesivir, remains a subject of study.

Factors That May Influence Kidney Health During Treatment

  • Pre-existing Conditions: Cats already battling kidney issues require even closer monitoring when undergoing GS-441524 treatment for FIP.

  • Dosage and Duration: Your veterinarian will tailor the dosage and treatment length for your cat; adhering to this plan is essential to minimize risk.

  • Interactions: It's vital to disclose all medications your cat's on, as some could impact kidney function or interact negatively with GS-441524.

Minimizing Risks: Proactive Monitoring

  • Blood Work: Your vet will closely track creatinine and BUN levels through regular blood tests, aiding in the early detection of any changes.

  • Urinalysis: This additional test offers insights into your cat's kidney health.

  • At-Home Observations: Stay vigilant – note hydration, urination, and your cat's general well-being; contact your vet with any concerns.

The Good News: EIDD-2801 (Molnupiravir) as a Promising Alternative

The oral antiviral EIDD-2801 (molnupiravir) presents an exciting option for FIP treatment. Studies and our own treatment protocol,  Remedy2801™ ([ illustrate its effectiveness against FIP, often with lower risks of kidney-related side effects.

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