Injections or Pills For FIP?

The applicability of injections or pills can vary by circumstance, by a cat's symptoms, and by a cat's demeanor, and depending if digestive tract issues like vomiting or diarrhea are present, so please understand that I am just offering my perspective after having given ten days of twice-daily injections (20 total injections) and the remaining 74 days (+14 as insurance) of pills to our boy Josh.

Dr. Pederson , the researcher who discovered that GS-441524 can cure FIP discusses oral dosing with GS pills in his paper. He provides useful information about GS brands and more.

Richard Malik DVSc PhD FACVS FASM Centre for Veterinary Education, The University of Sydney provides in-depth information about treatment via injections followed by pills in this article.

Our boy  Josh was not a typical FIP case (if there is any such thing)  because he was already in a battle for his life as a FeLV+ cat and our attention to his health was already heightened.

I did not know then, but now know that FeLV+ cats are more likely to develop the FIP mutation of FCoV.

July 11, 2022, I was having Josh's bloodwork and FeLV Quant PCR tests done to monitor his FeLV viral load and to evaluate if he had a measurable positive response the previous  30-days of  Retromad1 treatment for FeLV. (2x daily)  

As a result of posting his bloodwork for FeLV feedback in a Facebook group for FeLV/FIV cat owners, immediately alerted me that they saw indications in his bloodwork that he may have FIP. I had not idea what FIP was and no suspicion o fit since Josh was already FeLV and I thought that was all I was trying to help him fight.

Fortunately, his FIP was discovered early because Josh was rapidly declining daily.

It was a shock to figure out that he had FIP in addition to being FeLV+. (That's a whole other story)

July 2022 he had a 106.4 fever of unknown origin, was lethargic, had almost ceased eating, stopped playing, and weighed 9.4 pounds with a distended abdomen full of fluid when FIP was diagnosed.

When we connected with FIP Warriors, the admins recommended a 2.4ml dose of Aura 17 via injection twice daily (every 12 hrs).

The larger dose was recommended because of his being FeLV+.

Their recommendation was to give injections twice daily for at least two weeks and then if we wanted to we could switch to pills. The rationale for injections was that they assured the best absorption of the GS and guaranteed that it entered his system to do its magic.

Pills can have variable bioavailability, so if the cat is vomiting, etc. then pills may not be effective. Pills may also cost more.

Josh's response to GS injections was rapid, but his case may be different than your cat's.

The FIP Log site allows parents treating pets to log their treatment data and aggregates it with all others who log data. You may find the information on this site informative about GS brands, cost estimation, injections, pills, and more. 

I had NEVER given an injection to a cat (or a human) before, so I had NO experience.

It took two of us to dose him. One to hold and distract while I injected him.

It was an awful, painful and confusing experience for him and for us.

He surely wondered why we came into his room twice every day to hurt him and were guilt ridden about hurting him even though it was intended to save his life.

I dreaded every approaching injection because it was so painful for him.

I had no idea if his pain was because I did not know what I was doing or if the GS was causing the pain or both.

With each torturous shot, this previously gentle trusting boy began resisting more vigorously and his trust in us was deteriorating with every injection. I wanted to cry even though I hoped we were saving his life.

The sweet boy who previously would come eagerly when called was now running and hiding and avoiding me like the plague. He even began to bite firmly warning us to stop hurting him. He had NEVER done that before these injections.

Obviously, the injections being administered were hurting him and seriously stressing him. They were definitely stressing me and I was not even the one getting the painful injection.

I know from experience that STRESS lowers a cat's immune system effectiveness and every rescue and shelter can attest that upper respiratory infections are common when cats become stressed. Before being stressed their immune system can suppress the virus causing URI, but when stressed their immune system no longer functions as well and URI outbreaks are a common outcome.

Josh's immune system was already compromised by FeLV, so adding more stress for him seemed very counterintuitive, so I was looking for a way around increasing his stress every day for three months.

By day five of injections Josh was doing so much better.

His fever was gone, his appetite returned and his energy and playfulness returned to normal.

It was amazing because he had been declining daily before beginning GS and the vet wanted to euthanize him… again.

By day ten of injections he was doing so well that one would never know he had been sick and his abdominal fluid (almost a liter) had almost all fully reabsorbed.


In this paper, Dr, Pederson discusses effusion, reabsorption timelines, when to drain and when NOT to drain, and possible causes for persistent fluid accumulation during treatment.

Even though Josh was improving, I was getting more stressed with every  injection, so I decided we HAD to switch to pills.

I spoke to the admins because they had recommended two weeks of shots and we were only on day ten. They said that because we had been giving him such a high dose twice a day, it should be fine to switch him to pills earlier than planned.


The number of pills required to match and increase his injection dose was seven (7) of the ones we could get at that time. We first tried giving him the pills normally. That failed.

Next, we tried a pill shooter. That failed.

Then we tried hiding the pill in a dollop of Churu. He licked off the Churu and spit out the pills even when we only gave him pills one at a time. That failed.

I was beginning to think pills were going to be no easier to administer than injections.

Finally, I spoke to a rescuer who had treated and saved 20+ FIP cats and they advised placing the pills in a spoon and adding a few drops of water. They told me the pills would literally disintegrate when touched by water.  They also told me that the pills had no flavor.   I

That made me wonder how the same medicine in injections could be so painful and yet have no bitter or acrid taste in pill form.

I doubted their assertions until I tried them.

Previously, when a pill was placed in a dollup of Churu, the pills had not dissolved at all (possibly due to the grease content coating the pill and repelling moisture), but this time, sure enough, a few drops of water completely dissolved the pills on contact!

I placed his seven pills in a large spoon and added a few drops of water, then I added a dollup of Churu and mixed it all up with a toothpick. I placed the spoon in front of Josh and he eagerly licked it all up! Hallelujah!

From that day forward Josh was eager to take his GS and he loved the Churu. Over the next two weeks, he began to trust us again and gradually returned to his normal behavior toward us once we ceased torturing him. I was so happy.

Josh completed the remaining days of his 84 days of treatment taking pills dissolved and mixed with Churu. Since October 20, 2022 he has been in the 84-day observation period and doing great.

I know some may not recommend dissolving or crushing the pills, but for us dissolving them made administering them totally stress-free and based on Josh's progress the dissolved pills have been very effective.

Other pet owners have reported no trouble with injections or no trouble hiding pills in treats, etc. but for us, the dissolved pill in Churu was the purrfect solution. It may be for you, too.

In closing, I suggest that eliminating the stress of injections when feasible can beneficially support the powerful effectiveness of GS.

Your pet does not get to choose injections or pills; however, I submit that they do tell you their preference via their behavior.

The choice is yours.

Your admin can guide you about when pills are an option for your furbaby depending on their FIP circumstances. 

Using the oral form of GS-441524 during the early phase of FIP treatment may not be recommended due to ABSORPTION uncertainty.

The Feline Infectious Peritonitis (FIP)  virus is a mutation of the enteric FCoV virus often found in cats' digestive tract thus FIP originates in the digestive tract, then migrates to other organs throughout the body.

A compromised intestinal tract may have a reduced ability to digest and absorb GS into the bloodstream and unfortunately, it is not possible to know exactly how much GS-441524 is absorbed by the body when giving pills.

After Josh had received ten days of twice-daily 2.4 ml injections of Aura 17, he had not been vomiting or presenting any other digestive issues and had resumed eating normally so we assumed his oral absorption should be normal.

However, to increase our confidence about that we did increase his oral pill dose to a higher amount than his already high injection dose. We wanted to be as sure as we could that he would be absorbing an adequate amount of GS into his bloodstream. 

Oral pills of GS-441524 can be used to treat FIP effectively in the following situations and as advised by an admin:

  • When your cat's digestive organs are functioning normally.
  • When blood tests show that GS injections have brought viral infection under control and the body is recovering well.
  • When used as a preventative measure for cats that are suspected of FIP infection by the doctor.
  • When used after the conclusion of the treatment as a periodic immunity booster to avoid relapse.

The most effective method of delivering GS-441524 to your cat's bloodstream is via direct subcutaneous injections; however, if the stress of injections is very high, then that amount of stress can have a serious negative impact on the cat's immune system, and thus its ability to mount an effective immune response along with GS treatment.

In Josh's case, we assumed that an increased oral dose would help compensate for any absorption uncertainty.

Consider that an uncertain decrease in the bioavailability  (absorption uncertainty) of GS pills may not be any more harmful than the uncertain negative effects of the high stress of daily injections for 84 days.

This is just a personal assumption.

Pill dosing and cost will vary depending on the brand chosen. The following links are to different dose calculations by different companies to provide some insight into pill dosing and estimated cost.

I am not endorsing any particular brand, just providing information although we did use Aura liquid and pills.

Home Main

Dose Calculator

GS Calculator

GS-441524 Dosage Calculator

MUTIAN Capsules Dosage Calculator


  • My cat Little Lady hated pills so much I invested in kavalar gloves. FIP admin discouraged opening the pills due dosage loss. I understand their rational but there are humans who can not swallow pills therefore having a cat not liking pills is hardly far fetched.

    The shots were bad in that they caused sores but they were actually easier to give than the pills. It was misery having to struggle with her daily. Expenses quickly increased when the pill would dissolve on her head,in my hand or became stuck to the wall requiring another pill dosage.

    In desperation I combined knowledge from a checkered past with nursing knowledge gained from liquifying pills to put down g-tubes in humans unable to eat normally.

    The expense of pills and blood work left me broke and churu is rather expensive. I use a dab of human baby food – turkey or chicken. At $1.40 a jar that can last several days after opening if kept in the refrigerator.

    Her doses are rounded at a slightly higher weight that should easily compensate for the minimal amount of medicine lost.

    I will happily share my method if appropriate.

    • Feel free to share anything that may help others fighting for their furbabies lives.


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