Dosing for FIP depends on the form of FIP, as well as the individual cat's response to treatment. Typically the subcutaneous dosing for FIP is:
5-6 mg/kg for cases without ocular or neurological involvement
8 -10 mg/kg (minimum) for ocular FIP cases
10 mg/kg (minimum) for neurological FIP.
Ocular and neurological cases in particular may require higher doses depending on the severity of the neurological symptoms and how well GS passes through the blood/brain barrier in the individual cat.
For pills, only about 50% of the total amount of GS is absorbed. If the pills are labeled by actual GS content (such as with BOVA) then the dosing will be double the injectable dose. However most suppliers label the pills by their bioavailable content, in which case the dosing is the same.
Always consult with your veterinarian or treatment advisor if you have questions about your cat's dose.