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How Much Does FIP Treatment Cost? Comparing GS-441524 vs EIDD-1931

Summary

  • GS-441524 remains the most widely used treatment for feline infectious peritonitis (FIP), owing to high success rates and no side effects, but higher costs.

  • EIDD-1931 (MolnuFIP) and EIDD-2801 (Molnupiravir) are emerging as cost-effective alternatives, having similar effectiveness, but potential side effects at high dosage..

  • Typical GS-441524 treatments cost between $300-500 USD for kittens and $500 to $1,000 for adult cats (curefip.com), depending on the cat’s weight and the form of the disease.

  • EIDD-1931 lowers treatment costs by 40–60% compared to GS-441524, with similar efficacy.


How Much Does FIP Treatment Cost?

Breakthrough research led by Dr. Niels Pedersen and his team of veterinary virologists at the University of California, Davis, in 2018 demonstrated the effectiveness of GS-441524, paving the way for treatment-ready oral and injectable formulations supplied by companies such as curefip.com and basmifip.com.


Since then, the cost of GS-441524 therapy has dropped significantly—from tens of thousands of dollars per course in its early days to just a few hundred dollars today. Despite this decline, affordability remains a challenge for many cat owners.


Further progress came in 2022, when researchers successfully applied EIDD-2801 (Molnupiravir) and its parent compound EIDD-1931 as additional antiviral options for treating FIP. 


The primary advantage of these EIDD-class drugs lies in their ability to further reduce treatment costs, offering pet owners more affordable alternatives.


With multiple antiviral pathways now available, it is critical for owners and veterinarians to understand the benefits and limitations of GS-441524 versus EIDD-1931 (Molnupiravir). 


This guide provides a practical breakdown of real-world pricing, treatment duration, and total expenses, empowering pet owners to make informed choices without compromising safety or efficacy.


What Is GS-441524 and Why Is It So Widely Used?


GS-441524 is the nucleoside analog that first demonstrated curative effects against Feline Infectious Peritonitis in 2018. 


Today, many brands offer reputable and reliable GS-441524 in treatment-ready oral liquid form through compounding pharmacies such as Bova and Stokes or through online ecommerce websites such as CureFIP.com and BasmiFIP.com, in injectable and oral forms.


GS-441524 Cost Breakdown (as of 2025)


  • Dosing duration: 84 days (recommended)

  • Treatment cost per week: $50–$250+, varied based on brands, locations, and concentrations.

  • Average total treatment cost:

    • Small cats (less than 2 kg): $300–$500

    • Medium cats (2–4 kg): $500–$1000

    • Large cats (more than 4 kg): $1000+


What Drives Up GS-441524 Treatment Costs?


  1. High Production Costs The active pharmaceutical ingredient (API), GS-441524, is costly to synthesize and manufacture. This drives up the baseline cost of treatment compared to more widely available veterinary drugs.

  2. Limited Market Demand Because GS-441524 remains an unlicensed treatment—not formally approved by the FDA, EMA, or other regulatory authorities—production is restricted to smaller suppliers. The experimental status limits large-scale manufacturing, keeping demand fragmented and costs higher.

  3. Regulatory Barriers Without official approval, mainstream pharmaceutical companies cannot mass-produce or distribute GS-441524 through conventional veterinary channels. This leaves pet owners reliant on niche suppliers, further sustaining higher prices despite the treatment’s proven effectiveness and global recognition among veterinarians.


What are EIDD-1931 and EIDD-2801 (Molnupiravir), and How Do They Work?

What EIDD‑1931 Actually Is

EIDD‑1931 is the active metabolite of Molnupiravir (EIDD‑2801).  Molnupiravir was developed for human use against COVID‑19, with each authorised capsule containing 200 mg of active drug and a standard human regimen of 800 mg twice daily for five days. 

When treating cats, the situation is very different: veterinary guidelines recommend roughly 10–15 mg/kg of Molnupiravir every 12 hours and caution against exceeding 15 mg/kg because of toxicity.  

Molnupiravir is metabolised to EIDD‑1931, and both compounds have a narrower therapeutic window and more teratogenic concerns than the feline “gold‑standard” GS‑441524.  

For this reason, professional guidance suggests reserving EIDD‑1931 for cats that do not respond to GS‑441524 and only in regions where no other antivirals are legally available.

On veterinary formulations.

Because human Molnupiravir capsules are designed for 800‑mg doses, they must be carefully divided to achieve safe feline dosages—a process that requires precise measurement.  

Some compounding pharmacies provide smaller tablets (for example, 60 mg EIDD‑1931 tablets) that simplify dosing.  

However, these formulations are not FDA‑approved for veterinary use, and their potency can vary. Compounded Molnupiravir/EIDD‑1931 should only be used under veterinary supervision and with frequent weight checks, as cats often gain weight during therapy, necessitating dose adjustments.

MolnuFIP.com offers pre‑dosed EIDD‑1931 capsules designed for the treatment of FIP. In vitro testing of EIDD-2801 and EIDD-1931 exhibits cytotoxicity at high dosage levels. 

Molnufip.com recommends a dosage of 10-15mg/kg for the treatment of feline infectious peritonitis. If you intend to treat FIP using the EIDD class of medicine, it is recommended to choose molnufip.com’s pre-dosed capsules formulated for FIP treatments.

EIDD-1931 Cost Breakdown

  • Dosing duration: Up to 60 days

  • Cost per package (oral): $35–$75

  • Average total treatment cost:

    • Less than 2 kg: $35–$70

    • 2–4 kg: $75–$150

    • More than 4 kg: $150–$300

Additional Benefits of MolnuFIP’s EIDD-1931

  • Oral capsules, easy home-based treatments. 

  • Shorter treatment period, 30 to 60 days. 

  • Ideal for FIP relapse cases or when FIPV develops drug resistance to GS-441524.


GS-441524 vs. EIDD-1931: Pros and Cons.

Feature

GS-441524

EIDD-1931 (MolnuFIP)

Average Treatment Duration

Up to 84 days

Up to 60 days

Dosing Frequency

Every 24 hours

Every 12 hours

Total Cost Range

$500 - $2,500+

$30 - $300

Form Availability

Oral and injectable

Oral only

Suitable for Neurological FIP

Yes (with higher dose)

No

Veterinary Supervision Needed

Yes

Yes

MolnuFIP delivers results on par with GS-441524 for mild to moderate FIP—at a fraction of the cost.


When Is GS-441524 the Better Option?


While EIDD-1931 and EIDD-2801 are effective treatment options, GS-441524 remains the gold standard for FIP therapy.


Choose GS-441524 injections in cases involving:

  • Ocular or neurological FIP symptoms

  • Rapidly progressing disease

  • Cats with appetite loss, digestive issues, or pre-existing kidney and liver conditions


In these scenarios, GS-441524 provides faster viral clearance and is supported by the broadest clinical documentation to date.


Tips: Saving Money on FIP Treatments

  • Request a weight-based dosing chart before purchasing any antiviral.

  • Compare prices on the internet.

  • Avoid suspiciously cheap, overly expensive, or products/brands with no references. 

  • Avoid buying from individuals. They are often flippers of unknown or untested brands.  Medicines are not sold by individuals.

  • Join support groups to learn from owners who’ve completed treatment.

  • Discuss combo protocols with your vet, like combining antivirals with anti-inflammatory drugs, or switching from injections to oral treatment once your cat is stable, especially if cost is a major factor.


Final Thoughts: Choose According to Budget and Clinical Needs


The best FIP treatment for your cat depends on diagnosis, disease stage, budget, and local availability. GS-441524 remains the top choice amongst veterinarians, but it can be expensive for some pet owners.


EIDDD-2801 (Molupiravir) and EIDD-1931, offered in MolnuFIP.com, offer a more economical option to treat feline infectious peritonitis, with a growing body of evidence supporting its efficacy from veterinarians and researchers.


Both options require adherence to dosing and veterinary oversight. Do not attempt to treat FIP without consulting a licensed veterinarian.



Frequently Asked Questions (FAQ)


  1. What is the average cost of GS-441524 treatment for FIP?

The cost of GS-441524 treatment for FIP in cats typically ranges from $500 to $2,500+, depending on the form (oral vs. injection), the cat’s weight, and the severity of symptoms.


  1. Are EIDD-1931 or EIDD-2801 cheaper alternatives to GS-441524?


Yes, they are generally 50–80% cheaper than GS-441524, while offering similar treatment efficacy in most cases of FIP.


  1. Can I switch between GS-441524 and EIDD-1931 during FIP treatment?


Yes, switching is allowed, but should be supervised by an experienced FIP treatment advisor to avoid treatment regressions or failures. Dosage adjustments are needed.


  1. How can I reduce FIP treatment costs without compromising success?


Start treatment early, choose the correct treatment method based on the severity of the symptoms, and use verified, high-quality brands mentioned above. Get dosage guidance from veterinarians or brand representatives.


  1. Which brands offer both GS and EIDD at fair prices?


Reputable providers like Cure FIP™ and  Basmi FIP™ offer GS-441524. MolnuFIP™ offers EIDD-1931 with proper documentation, treatment advisory, dosage guidance, and global availability.



Conclusion


  • GS-441524 is the most proven FIP treatment, but it can cost $500–$2,500+ per treatment.

  • MolnuFIP.com (EIDD-1931) offers a lower-cost alternative, starting from $35 per treatment.

  • Both GS-441524 and EIDD-1931 require daily dosing and veterinary supervision.

  • EIDD-1931 offers a shortened treatment period of 4–8 weeks when compared with GS-441524.

  • Treatment costs depend on cat weight, disease severity, and product source.

 
 
 
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