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Easy to use oral capsules for FIP Treatment |

Updated: Nov 15, 2023

What is Feline Infectious Peritonitis (FIP)?

Feline infectious peritonitis (FIP) is a viral disease caused by feline coronavirus. It is a rare but fatal disease if left untreated. Until recently most FIP treatment using GS441524 anti viral has been done through subcutaneous injections, commonly referred to as the injection form, which can become extremely painful to cats after days of continued treatment. Injections become increasingly difficult to administer due pain caused by injection fatigue and skin sores. Many cat owners and veterinarians prefer the oral form of GS441524 antiviral drug for the treatment of FIP. Today, we will take a close look at oral version of GS441524, how it compares to the injection form, what are the advantages and disadvantages of each form, and when should we avoid using oral form.

Two treatment options for FIP

There are 2 ways to provide GS441524 antiviral nucleoside analog to cats: through subcutaneous injections or through oral capsules and pills. Veterinarians generally prefer injections. Injections allow an exact control of dosage and rapid absorption. Cat owners, in contrast, generally prefer oral forms to spare their cats from the pain of daily injections. Some cats exhibit strong reactions to injection pain, especially towards the latter stage of the FIP treatment. Some cats develop an aversion to injections after days or weeks of continued jabs. Some cats may struggle furiously at the sight of syringes or veterinarians who perform daily injections. Injection site sores may develop in some cats due to the highly acidity of injectable GS441524. In these cases, oral GS capsules or pills are the ideal alternatives to injections.

Giving GS-441524 oral medication
Giving GS-441524 oral medication

Oral medication has been around for several years. Until recently veterinarians didn't trust GS441524 delivered via the oral route due to questions concerning bioavailability and absorption rate. However sentiments amongst veterinarians began to change in the 2020 as an increasing number of cats with wet or dry FIP were successfully treated vial oral administration of GS441524. Initial concerns of possible drug resistance to oral administration by researchers from UC Davis was proven unfounded. Through thousands of cats, oral GS441524 has demonstrated its reliability in treating FIP.

What are the differences between oral forms capsules and tablets?

While the effectiveness of oral capsules and pills are comparable, capsules are easier to administer than tablets. Capsules are coated with a smooth surface for easy ingestion. Any unpleasant taste is locked away from the taste buds. Once reaching the back of the tongue, cats can not regurgitate the oral capsules, which some cats can do with tablets. Capsules can be administered in 3 ways. Video of how to administer oral capsules

  • by adding wet cat snacks on top of the capsules, in which case cats would eat the capsules whole.

  • by inserting capsules directly into the cat's mouth. Due to its smooth texture and absence of taste, cats readily swallow capsules without struggle.

  • by mixing the content of the capsule with normal cat food.

The disadvantage of capsules is that they are more costly to manufacture. Thus, capsules are less preferred by manufacturers. is currently the only brand that offers oral GS in capsule form.

FIP tablets in contrast are faster and cheaper to manufacture. There are many brands that offer tablets for treating FIP. Mutian and Aura/Spark, Capella, Lucky, Brava, and Kitty Care are popular brands that offer oral tablets for the treatment of feline infectious peritonitis. FIP oral tablets are generally uncoated. They are small in size and can be administered without too much struggle in a majority of cases. However, in a small number of cases, due to their taste and texture, some cats exhibit a gaging response and may spit out the tablets if they have not travelled far enough down the oesophagus, forcing the caregiver to repeat the process. Worse yet, some cats may vomit out the tablets shortly after ingestion, an unpleasant experience and financial waste for cat owners.

While tablets are easier and cheaper to manufacture, the disadvantage is that manufacturers need to include chemical additives, also known as inactive pharmaceutical ingredients to ensure that the pills bind together and don't clog up the machines.

Muttian oral pills
Mutian oral tablets

One additional factor to consider when using oral GS treatment is the bioavailability of GS-441524 in oral form. Unlike subcutaneous injections that go directly into the bloodstream, oral GS capsules and tablets need to travel through the digestive system before being absorbed into the body. According to published research papers, a healthy cat normally absorbs between 40-50% of the GS-441524 given orally. Thus a dosage of greater than 10mg/kg is needed in the oral form to ensure effective treatment of FIP. Only in dosage greater than 10mg/kg can GS441524 cross the blood brain barrier and arrest the replication of viruses that have already reached the brain and the nervous cells according to researchers. Some manufacturers provide a fix amount of GS per tablet. Cure FIP™ does it differently by providing a simple to follow weight class based oral capsules. Each capsule contains 2.5x of GS-441524 in order to avoid under-dosing that may lead to treatment regression and FIP relapses.

When is it appropriate to use oral GS for FIP treatment?

Injections are still the most direct and reliable method in treating FIP infections. Therefore, it is always advisable to start FIP treatments with injections rather than oral pills. Generally we recommend completing a minimum 30 days of injections before switching to oral meds. Below are conditions that favours injections over oral GS for as long as the condition persists.

  • frequent vomit and diarrheas

  • liver and kidney complications

  • kittens

  • inherent poor immunity

  • inherent poor digestion and/or nutrition absorption

  • neurological and ocular symptoms

If your cat suffers from one or several of the above mentioned conditions, then oral GS treatment should be avoided. If after taking oral for several days, your cat's condition regresses noticeably, you should immediately increase the dosage or consider switching to injections for the remaining days of the FIP treatment.

Cost Comparison between Injection and oral GS-441524

The price of oral GS varies greatly from one brand to the next. Added to the confusion is that each brand has their own way of calculating and dispensing dosage. Treatment effectiveness also varies due to confusing dosing regimens that are brand specific. offers one of the simplest oral GS dosing schedule compared to other brands. GS capsules are offered in 3 different weight classes. Provide 1 capsule per day based on the weight class your cat belongs to.

While GS is still a black market product, the price of injections and oral pills have reduced dramatically since their first introductions several years ago. Today the cost of GS oral treatment can range from a few hundred dollars to a few thousand dollars depending on the brand and the weight of your cat.

Do oral FIP treatments cause a higher relapse rate?

FIP research has demonstrated that oral FIP treatment, when administered at the appropriate time and correct dose, can be as effective treating feline infectious peritonitis as subcutaneous injections. However, it is generally acknowledged by FIP treatment experts that cats are subject to a higher risk of relapse when given oral treatment when compared to injections. Oral pills have proven not as effective in treating cats suffering from neurological and ocular forms of FIP, or from digestive problems such as frequent vomiting and diarrheas.

There are currently no known side effects from taking FIP oral meds.


Thanks to the scientific discovery by research teams in the USA and manufacturers in China, FIP treatment choices are becoming ever more diverse and accessible. While injections are still considered the more reliable method of treating FIP, oral capsules and pills are now used widely and successfully to treat feline infectious peritonitis infections. Use oral form of GS441524 only under the correct conditions to avoid relapse of symptoms in the future. Treatment success often depends on the experience and expertise of your vet. If your vet is not experienced treating feline infectious peritonitis, you may contact us for advice and guidance. Our email is

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