The dosing protocol recommended by FIP Support optimizes dosage and duration according to the dry and wet forms. The content of this page is treatment guidance; actual dosage should follow the final judgment of a veterinarian.
Rather than antiviral medication alone, combining it with anti-inflammatory and organ-protective measures can improve the prognosis.
To suppress inflammation from vasculitis and granulomas, always use in combination. Use for about 10 days from the start of treatment as a guide, and avoid long-term continuous use. Because oxidative stress in the body is thought to remain high even after 10 days, also consider antioxidant supplements (vitamin E, CoQ10, SAMe, glutathione, resveratrol, broad-spectrum CBD, etc.).
To reduce the burden on the liver from long-term treatment, we recommend combining where possible. Monitor with regular blood tests during the treatment period.
Through the unstable early phase (at least about one week), injections reliably maintain blood concentration; switch to tablets once the condition stabilizes. In cases with neurological or ocular signs, continue injections until those signs have fully resolved.
The doses shown are guidelines. The veterinarian flexibly adjusts dose and duration according to symptom improvement and changes in body weight.
Because treatment is long (84 days as standard, longer for neurological or ocular cases), maintaining the owner's motivation and reliable daily dosing is important. If an owner asks to reduce the dose because the cat looks better, explain the risk of relapse.
Improvement in general condition does not mean healing inside the brain and eyes. Where neurological or ocular signs are involved, maintain the higher dose (equivalent to 0.8–1.0 ml/kg by injection) and complete the full course.
Because of the blood-brain barrier, GS-441524 reaches only about 7–21% of plasma concentration in the brain and eyes. Resolving effusion, a normalised A:G ratio, and returning appetite show improvement outside the brain and eyes — they cannot rule out residual virus within them.
Switching to oral too early (oral absorption is under 50% of injection, so the same stated dose delivers roughly half) / reducing on apparent recovery (concentration in the brain falls with it) / ignoring weight gain (holding the dose steady is an unnoticed reduction).
Maintain the higher dose and never reduce part-way / continue injections until neurological signs have fully resolved, then move to oral / weigh weekly and recalculate the dose on current body weight (increase as the cat grows).
| Item | Dry form | Wet form | Neuro / ocular signs |
|---|---|---|---|
| Initial injection period | at least 1 week | at least 1 week | until signs fully resolve |
| Recommended injection dose | 0.6 ml/kg | 0.52 – 0.60 ml/kgmixed form assumed | 0.8 – 1.0 ml/kg |
| Injection dose range | 0.6 – 0.8 ml/kgup to 1.0 with neuro/ocular signs | 0.4 only if purely wet | no reduction on improvement |
| Oral tablet reference60 mg / tablet | 1 tablet per 2 kgunder 1 kg: 0.5 | 0.75 tablet per 2 kgunder 1 kg: 3/8 | 1 tablet per 2 kgafter signs resolve |
| Oral tablet by weightonce daily | ≤2 kg: 1 / ≤4 kg: 2 | ≤2 kg: 0.75 / ≤4 kg: 1.5 | ≤2 kg: 1 / ≤4 kg: 2 |
| Total treatment period | usually 84 days | usually 84 dayscomplete even if remission | 84 days or longeruntil criteria are met |
Set the dose by form
and symptoms (84-day course)
Combine with anti-inflammatory
and liver-protective drugs
Observe continuously and
adjust the plan as needed