Neurological FIP in Cats: Signs, Diagnosis & Treatment

Neurological Feline Infectious Peritonitis (FIP) is a form of FIP where the mutated feline coronavirus reaches the brain and spinal cord, causing signs like wobbliness, head tilt, seizures, and disorientation. It is one of the most serious forms of the disease, yet it is treatable today with antiviral care. Treatment usually starts with daily GS-441524 injections at the higher neurological dose, and your cat's odds are better than they have ever been.

If you have just heard the word "neuro FIP" from your veterinarian, take a breath. You are not the first Pawrent to face this, and there is a real plan ahead. Let us walk through it together.

A cat resting comfortably at home.

What is neurological Feline Infectious Peritonitis (FIP)?

Neurological Feline Infectious Peritonitis (FIP) is the form of FIP that attacks the central nervous system, meaning the brain and spinal cord. It develops when the common feline coronavirus (FCoV) mutates and spreads into nervous tissue.

FIP has four distinct forms: wet (effusive), dry (non-effusive), ocular, and neurological. Neurological FIP and ocular FIP are two separate forms, not sub-types of the dry form, and a cat can sometimes show signs of more than one form at once.

What makes the neurological form special is location. The virus sits behind the blood brain barrier, a natural filter that protects the brain. That barrier also makes the neuro form harder to reach with medicine, which is why the dosing is different from wet or dry FIP.

What are the signs of neurological Feline Infectious Peritonitis (FIP)?

The signs of neurological Feline Infectious Peritonitis (FIP) come from the brain and spinal cord, and they often look like a loss of coordination or control. Common neurological signs include seizures, head tilt, loss of balance, paralysis, and disorientation.

You might notice your cat:

• Wobbling, stumbling, or falling to one side

• Holding the head at a tilt

• Having seizures or sudden tremors

• Seeming confused, lost, or unusually withdrawn

• Dragging a limb or losing use of the back legs

It helps to know what belongs to a different form. Eye colour change, cloudiness, and inflammation inside the eye (uveitis) are ocular signs, not neurological ones. If your cat has both eye changes and balance problems, tell your veterinarian, because the treatment dose covers both.

General FIP symptoms can appear too, such as a lingering fever that does not respond to antibiotics, weight loss, poor appetite, and low energy. Neurological signs on top of these raise concern for the neuro form.

How is neurological Feline Infectious Peritonitis (FIP) diagnosed?

Neurological Feline Infectious Peritonitis (FIP) is diagnosed by your veterinarian using a combination of clinical signs, blood work, and sometimes advanced imaging or fluid analysis, because no single quick test confirms it alone. There is a clear path forward, and it starts with the right diagnosis.

Your veterinarian will usually begin with these steps:

1. A full history and physical exam, paying attention to balance, reflexes, and behaviour.

2. Blood tests that often show changes such as high globulin, a low albumin to globulin ratio, anaemia, or high bilirubin.

3. Imaging or cerebrospinal fluid (CSF) analysis in some cases, to look for inflammation around the brain and spinal cord.

4. Ruling out other causes of neurological signs, such as injury, toxins, or other infections.

Because the neuro form hides behind the blood brain barrier, confirmation can take a little patience. The important thing is to start the conversation early, since beginning antiviral treatment promptly gives your cat the best chance.

Why is neurological Feline Infectious Peritonitis (FIP) harder to treat?

Neurological Feline Infectious Peritonitis (FIP) is harder to treat than the wet or dry forms because the medicine has to cross the blood brain barrier to reach the virus in the brain and spinal cord. This is why neurological FIP is dosed higher than the other forms.

For the GS-441524 injectable, the standard dose for neurological FIP is 10 mg/kg, compared with 6 mg/kg for wet FIP and 8 mg/kg for dry FIP. The higher dose helps more of the antiviral reach nervous tissue.

This higher dosing fits current clinical practice. In the systematic review by Gokalsing et al. 2025, the best outcomes were seen in the 5 to 10 mg/kg once-daily range, adjusted for the FIP form and for neurological or ocular signs. In the cohort reported by Ansari Mood et al. 2025, the mean starting dose for neurological and mixed cases was 9.65 mg/kg, adjusted upward as needed.

What treatment options work for neurological Feline Infectious Peritonitis (FIP)?

Treatment for neurological Feline Infectious Peritonitis (FIP) starts with daily GS-441524 subcutaneous injections at the neurological dose of 10 mg/kg, and after 2 to 4 weeks many cats switch to oral capsules to finish the course. This injection-first approach is common practice for neurological and ocular cases, because it establishes strong antiviral levels before moving to pills.

Here is what each part of the plan looks like.

The injection phase

The GS-441524 subcutaneous injectable (40 mg/ml, 99.4% purity as a brand figure, in an 8 ml vial) is given once daily, 7 days a week, at 10 mg/kg for the neurological form. The full injectable course runs 12 weeks (84 days). Your veterinarian will weigh your cat regularly and adjust the amount.

The oral capsule phase

After 2 to 4 weeks of injections, once your cat is stable, many families switch to oral capsules to complete treatment. This is where you have two routes to discuss with your veterinarian:

• The dual capsule (GS-441524 + EIDD-1931). The key advantage here is simple: one capsule a day for your cat's weight class, with no mg calculation and no counting pills. You pick the capsule for the weight band, and that is the dose.

• FipX (EIDD-1931 capsule), 15 mg per capsule, 60 capsules per bottle. This EIDD-1931 oral option is dosed by weight every 12 hours, with the exact count set by your veterinarian.

The oral phase matters for the neuro form because EIDD-1931 is a small molecule antiviral used to continue the fight at home, including in ocular and neurological cases that have moved past the injection start.

Dual capsule dosing by weight class

Weight class	Dual capsule dose
0 to 2.5 kg (0 to 5.5 lb)	1 capsule per day
2.5 to 5 kg (5.5 to 11 lb)	1 capsule per day
Over 5 kg (over 11 lb)	1 capsule per day

One capsule a day for the right weight class keeps dosing easy during the long weeks of recovery. The recommended dual capsule course is 12 weeks.

GS-441524 injectable dose by FIP form

FIP form	Standard GS-441524 dose
Wet (effusive)	6 mg/kg
Dry (non-effusive)	8 mg/kg
Ocular	10 mg/kg
Neurological	10 mg/kg

You can read more about planning a full course in this guide to FIP treatment cost and protocol length in India, and if you are sourcing medicine, this safe GS-441524 sourcing guide can help you buy with confidence.

What results can you expect from neurological Feline Infectious Peritonitis (FIP) treatment?

Many cats with neurological Feline Infectious Peritonitis (FIP) respond well to GS-441524 based antiviral treatment, and families often see brighter eyes, steadier steps, and a returning appetite within the first weeks. Results are statistics, not promises, and every cat is different, so your veterinarian is your best guide to your own cat's progress.

The numbers behind the approach are encouraging. In the cohort reported by Ansari Mood et al. 2025 of 629 cats treated with GS-441524 (subcutaneous and/or oral) for at least 12 weeks, survival was 94.12%, meaning more than 9 out of 10 cats survived. In the systematic review by Gokalsing et al. 2025 across 11 studies and 650 cats, overall success was 84.6%, so more than 8 out of 10 cats were treated successfully.

For the dual antiviral approach of GS-441524 + EIDD-1931, our own data from about 46 treated cats showed remission in 78.3%, or about 8 out of 10 cats on the dual antiviral reaching remission. Across the wider network, more than 100,000 cats have been treated, saved, and helped since 2019, including cats treated with GS-441524.

These figures come from different groups of cats, but together they point one way: neuro FIP is no longer a hopeless diagnosis.

What should you avoid during Feline Infectious Peritonitis (FIP) treatment?

During Feline Infectious Peritonitis (FIP) treatment, a few common products can get in the way of recovery, so it is best to avoid them unless your veterinarian says otherwise. Keeping the plan clean helps the antiviral do its job.

Ask your veterinarian before using any of these during FIP treatment:

• Fluoroquinolone antibiotics

• Spot-on flea medications

• Lysine supplements

• Immune boosters

Some EIDD-1931 containing products, including FipX and the dual capsule, are not for pregnant, nursing, or breeding cats, and they are not for cats that cannot eat or defecate normally. The dual capsule is also not for cats with vomiting or diarrhoea, or for cats under 1 year old with wet (effusive) FIP. Your veterinarian will confirm your cat is a good fit before you start.

How can supportive care help during Feline Infectious Peritonitis (FIP) treatment?

Supportive care helps during Feline Infectious Peritonitis (FIP) treatment by giving the organs a little extra backing while the antivirals do the real work. These supplements are adjunct support only, not antivirals, and they never replace GS-441524 or EIDD-1931.

For example, LiverRx is a nutraceutical with SAMe, Silybin A+B (milk thistle), Vitamin E, and Vitamin C, and KidneyRx is a nutraceutical with ingredients like Omega-3, L-Carnitine, and cranberry extract. Used alongside veterinary-guided antiviral treatment, they can offer gentle organ support during the long weeks of recovery. Always clear any supplement with your veterinarian first.

FAQ

Can neurological Feline Infectious Peritonitis (FIP) be cured?

Neurological Feline Infectious Peritonitis (FIP) can respond very well to GS-441524 based antiviral treatment, and many cats reach lasting remission. Results are statistics rather than guarantees, so work closely with your veterinarian to track your own cat's progress.

Why is neuro FIP dosed higher than wet or dry FIP?

Neurological Feline Infectious Peritonitis (FIP) is dosed at 10 mg/kg for the GS-441524 injectable because the medicine must cross the blood brain barrier to reach the virus in the brain and spinal cord. Wet FIP is dosed at 6 mg/kg and dry FIP at 8 mg/kg, since those forms do not need to reach nervous tissue.

How long does treatment for neurological Feline Infectious Peritonitis (FIP) take?

Treatment for neurological Feline Infectious Peritonitis (FIP) usually runs 12 weeks (84 days), starting with daily GS-441524 injections and often switching to oral capsules after 2 to 4 weeks. Some cats need a longer course, which your veterinarian will decide based on response.

What is the easiest oral option for the neuro form?

After the injection phase, the dual capsule (GS-441524 + EIDD-1931) is the simplest to give, because it is one capsule a day chosen by weight class: 0 to 2.5 kg (0 to 5.5 lb), 2.5 to 5 kg (5.5 to 11 lb), or over 5 kg (over 11 lb). FipX (EIDD-1931) is another oral route your veterinarian may suggest.

Is there a refund if I change my mind?

Yes. You can cancel any time before your order ships for a full refund. There are no guarantees of a cure in medicine, but there is a clear, supported treatment path and a team to walk it with you.

Facing neuro FIP is hard, but you do not have to do it alone, and your cat's recovery journey can start today. To explore the treatment options and build a plan that fits your home and budget, talk with the BasmiFIP India team and your own veterinarian. Together you can choose the next right step for your cat.