GS Protocol

Selecting a Form of GS:

When deciding between oral versus injectable, it’s not simply a matter of owner’s preference. Cats who are gravely ill, not eating on their own, or experiencing vomiting or diarrhea should not start out on the oral form, as GI upset may interfere and/or hinder absorption of the medicine.  These cats should start with injectable and if desired, switch to oral once they are stable. If the cat is stable at the time treatment is started, typically either form is acceptable.

Other considerations are price, ease of administration, and side effects.


  • Pro: Price. Most of the injectables are significantly less than the oral form
  • Pro:  Precision in dosing. You can adjust the daily dose to the exact weight of the cat, whereas the oral form is dosed based on weight range.
  • Pro: Medicine is not dependent on the digestive system and is fully absorbed into their blood stream, so they are guaranteed to be getting the maximum benefit of the GS.
  • Pro: The field study was completed using injectable, so there is  professionally curated data available.
  • Con: Injections sting and some cats do not tolerate the pain well.
  • Con: Injection site sores are likely going to happen, regardless of how carefully the shots are administered. In most cases, the sores will heal on their own with little to no need for intervention.

Oral capsules/tablets:

  • Pro: Ease of administering. Many cats will take the capsules/tablets willingly if coated with a treat or given in a pill pocket.
  • Pro: The oral forms are readily available at all times.
  • Con: Price. The oral form is considerably more expensive than injectable.
  • Con: Dose is not precise. The capsules and pills can only adjust to 0.5kg weight increments.
  • Con: GI issues. If the cat is already having GI issues before starting treatment, the absorption of meds is questionable, at best. Also, several cats using mutian capsules experience vomiting and/or diarrhea, in which case little to no medicine may have been absorbed and the dose needs to be repeated. Spark has not had GI side effects.
  • Con: Lack of data. There are no field studies for the oral form, so no confirmed data.


Injectable: There are currently 5-6 brands of injectable that members have used and can vouch for. These range in price from $80/vial to $358/vial.  The daily dose is determined by cat’s weight, type of FIP and the concentration of the selected brand. A dose calculator and cost estimator can be found here. The price of each brand is identified in the calculator.

Oral: There are 2 options for oral meds.  The daily dose depends on the cat’s weight and type of FIP. 

With Mutian capsules, the price works out to $16/kg per day for wet or dry FIP. For ocular FIP, the price is $24/kg per day and for neuro, $32/kg per day.  Mutian capsules are given once a day for 84 days. 

Spark pills are priced at $10.40/kg per day for wet/dry,  $15.60/kg per day for ocular, or $20.80/kg per day for neuro. 

Mutian and Spark both offer an identical guarantee. If you use their brand for the full 84 days and your cat is not cured, additional meds will be provided for free until the cat is cured. The guarantee is for wet and dry FIP only and does not apply to ocular or neuro  cats. 


If you are interested in Mutian, you can order from their website,, after speaking with an admin who will instruct on dosage.  Capsules can be purchased from their online store. Their injectable can be ordered thru the chat feature on their website. 

For all other options, contact an admin.  

*** Some brands are not always available and you may need to start with whichever is available the fastest. Untreated, this virus progresses very quickly so starting any brand as soon as possible is recommended. You’re not locked into any particular brand though. You can switch brands at any time, and you can switch between injectable and oral as well.*** 

Storing GS

Injectable GS has a shelf life of 6 months at room temp, or may be refrigerated for up to a year.  All brands need to be stored in a dark place, away from direct light. 

Oral GS has a shelf life of 1 year, and should also be stored in a dark place, away from direct light. 


For oral treatment, consider a pill popper, pill pockets, Churu or Delectable Lickable cat treats to coat the capsules/tablets.

For injectable treatment, you will need 3cc syringes, 25G needles for drawing out the liquid and 20-22G needles for the injection. Luer-locking needles and syringes work best. You can purchase these through your vet, farm supply stores, or Amazon.  Many parents use a cat-sack or comparable  restraint. Many also use Gabapentin as a mild sedative 2 – 2.5 hrs before the injection. 

There may be some additional supplies needed, based on individual cat’s symptoms. Refer to “supplements” section. 


Administering Capsules/Tablets


For Mutian capsules, the cat mustn’t eat for 1 hour before and 30 minutes after. The capsules can be coated in butter, cat treat, or given in pill pockets, but refrain from giving a meal. Their stomach needs to be empty/acidic in order for the medication to be properly absorbed.  Wash the pills down with a syringe of water, chicken broth (no onions or garlic) or tuna juice. 

For Spark pills, the cat must fast for 30 minutes before and 30 minutes after both doses. Again, it’s fine to coat the pills  or use a pill pocket, but refrain from feeding a meal. Wash the pills down with a syringe of water, chicken broth (no onions or garlic) or tuna juice. 


Mutian capsules are given once per day, and should be given as close as possible to the same time every day. 

Spark pills are given twice per day, as close to every 12 hours as possible. 

With either brand, if you have a planned event that will prevent giving at the scheduled time, it is better to give earlier than later. If something arises unexpectedly and you have to give later than normal, give as soon as possible and resume the normal time the following day. 


Mutian capsules are dosed at 100mg/kg for wet or dry FIP, 150mg/kg for oculari FIP, or 200mg/kg for neuro FIP. 

Spark pills are given twice per day.  Wet or dry FIP is dosed at 1 pill per kg, two times per day.  Ocular is dosed at 1.5 pills/kg, twice a day and neuro kitties are dosed at 2 pills/kg, twice per day. 

The dosage depends on your cat’s weight and symptoms.

Side Effects:

If your cat vomits the pills, give another dose. If this happens more than once, consider switching to injectable. 

Administering Injections

Timing: Injections are given once daily, for 84 days. The shot should be given as close as possible to the same time every day. If you know in advance that you cannot give am injection that the usual time, it’s better to give earlier versus later. If life happens and you have to give later than usual, give as soon as possible and resume the normal time at the next dose. 

Preparation: Use a 25G needle for drawing the GS into the syringe. Discard the fill needle and replace with a fresh, sterile 20-22G needle for injection. If you’ve stored the GS in the refrigerator, allow the dose to warm to room temperature before administering. If you are using Gabapentin as a sedative, give 2 – 2.5 hours before the injection for maximum benefit. 

Type of Injection: GS is given sub-cutaneous. 

Restraints: Every cat responds differently to this. Some will freak more by being restrained than they will be the actual injection. Some will stay still with just a light hold by their human, while others need to be burrito wrapped in a towel, cat sack, or similar. Search the group for dozens of tips and videos to see what works for others but ultimately, it comes down to what works best for you and your cat. 

Dosage:  The dosage for wet or dry FIP is 5mg/kg. Ocular and/or neuro FIP should start at 8mg/kg and may increase incrementally to 10mg/kg if symptoms are not resolving at the starting dosage. 

The daily dose depends on the cat’s weight, form of FIP, and concentration of the brand used.  A dose calculator can be found here. 


Leakage: If any GS gets on their skin, clean the area with cool water and Dawn dish soap. If you’re able to estimate how much was lost, administer a partial dose to compensate for that loss. If the shot goes straight through and entire dose is lost, give a full dose immediately. 

Side Effects: Your cat will get injection site bumps or lesions, no matter how careful you are or which brand you use. These will heal on their own with no need for intervention most of the time. You can use Vetericyn if desired but most importantly, just watch for any sign of infection (discoloration, hot to the touch). If your cat is licking or scratching the area excessively, many members use an infant t-shirt or onesie to cover the sores.  The injections sting. It’s not uncommon for cats to be very vocal during and immediately following the injection. If you happen to hit a muscle or nerve, the cat might limp for several hours afterward. Many cats experience sneezing or excessive tiredness. 

Supportive Care/Supplements:

Cats who are in critical condition when starting GS are going to require supportive care and/or supplements until the GS has time to work and they are stable. Also, cats who have and/or develop a secondary condition may require additional care. 

If the cat is anemic, injectable B12 is essential. Severely anemic cats may require a transfusion. 

If the cat has Hyperbilirubinemia and/or is jaundiced, sub-cu fluids and Denamarin are needed. 

If the cat is not eating and/or is nauseous, an appetite stimulant and/or anti-nausea medication may be needed. 

Most cats are given an anti-biotic or anti-viral at the start of treatment, in case of secondary infection. Most cats are also given a short course of Prednisolone at the beginning, as it acts as an anti-inflammatory, and helps to keep the cat feeling brighter. With wet FIP, it can also help to slow the progression of fluid accumulation. 

Within 1-2 weeks on GS, all other medications and supplements will likely not be needed, unless the cat has a secondary condition that requires an additional medication.  

For more info, please review the pages on Supportive Care and Supplements

Recommended Lab Work:

Ideally, it’s recommended to run a CBC and Chemistry panel before treatment, and repeat at 4 weeks, 8 weeks, and prior to stopping treatment.  For cats with dry FIP, an ultrasound is also beneficial before stopping treatment. 

During the 12 week observation period, the recommendation is to repeat labs at 4, 8 and 12 weeks. 

After the observation period, cats should have follow up labs every 6 months for the first year, then annually thereafter. 

DO’s and DON’Ts of FIP Treatment:

  • DO: Start treatment ASAP. This virus progresses quickly. 
  • DO: Provide sufficient supportive care for your cats symptoms, as needed. 
  • DO: Ensure your cat is getting 200 calories and 60ml of fluid every day, minimally. 
  • DO: Give your cat the correct dose, at the correct time, every day. If you cannot be available at the scheduled time, giving earlier is better than later. If you must be later than usual, give as soon as possible and resume the usual tat the next dose.  
  • DO: Weigh your cat regularly, once a week minimally, and adjust the dose accordingly.
  • DO: Monitor your cat’s symptoms closely and seek advice if any new symptoms arise. 
  • DO: Seek immediate vet care if your cat is experiencing an emergency situation.
  • DON’T: Allow a cat to go days without eating. Syringe-feed if necessary. 
  • DON’T: Under-dose or skip doses.
  • DON’T:  Give any other medications that can have neurological side effects. This includes seemingly benign flea/tick topicals, flea collars, some dewormers. When in doubt, ask the group. 
  • DON’T: Vaccinate a cat while treating, or during the observation period. 
  • DON’T: Subject a cat to any elective surgeries while treating or during the observation period.

Dedicated to all FIP angels.

All information contained on this website is compiled from real-life experiences of cat owners who are currently, or have previously treated their cats for FIP.  Most of us are not veterinarians and the  information provided within is not intended to substitute or replace medical care by a licensed veterinarian. 

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