https://www.zenbycat.org/blog/dr-pedersens-faqs-about-using-gs
Please note that these answers were provided by Dr. Pedersen individual cat owner. Consider them as a useful guide and not as individual veterinary advice. In no case do they replace standard veterinary care.
General questions about GS-441524 injection
What if my cat doesn't respond to GS immediately or her behavior doesn't change after a few weeks on the drug?
All we can do is watch what is happening over the next few days and hope for the best. If increased pain develops at the injection site, it is possible that this is the cause of the symptoms we are seeing. If the place is sensitive to touch, it goes without saying that it bothers the cat. It is possible that the situation will worsen and an open wound will form in the painful area, or it will improve quickly. Even if no one wants severe reactions at the injection site, injection is still a better choice.
My cat experiences "ups and downs" during treatment. Sometimes it seems full of energy, other times it is lethargic. It is normal?
The most dramatic improvement usually occurs in the first week, or the first two, after which the process slows down. Do these cycles show that the cat is less active after the injection and more active a few hours after the injection? During our tests, we noticed that some cats seemed a little depressed and depressed after the injection. A higher dose worsens the situation. If it is a relapse, the reaction is even more pronounced, but if it is really just a reaction to the drugs, we will have to wait and see what happens after the end of treatment.
What should I do if my cat feels increased pain at the injection site from using GS? Would lidocaine or anything else help with the pain?
We are working to change the diluent for the drug to reduce stinging and pain, but it will probably take several more months and it will only solve the problem with the diluent and the effect of the drug itself. Applying lidocaine cream to the post-injection area is like locking the barn door after the horses get out. We tried to use it at the injection sites before treatment, but the owners who tried it were not satisfied with the results and stopped using it.
Is it safe / appropriate to continue administering FIO (feline interferon omega) concurrently with GS?
It won't help, it won't hurt either.
Should my cat continue in pre-zone with GS?
Not. You can stop prednisolone after a few days. A cat with FIP should respond very quickly to treatment and no other medication is needed at this time unless clearly indicated.
What are the chances that after a cat is cured of FIP, it will become infected again with a coronavirus that mutates again to FIPV? Should I treat a cat that secretes coronavirus?
Although theoretically possible, we have not yet seen the FIP-cured cats develop the disease later. Therefore, I would focus on curing your FIP positive cat. Do not treat a cat that only secretes enteric coronavirus. This cat has a very low risk of developing FIP and treatment with enteric coronavirus carriers will only promote the occurrence of drug-resistant strains.
Should I vaccinate or neuter my cat during GS?
Vaccination or castration is not required during treatment. Healing the cat is paramount. There will be plenty of time after treatment to resolve the issue of castration. Personally, I am not a strong supporter of FVRCP vaccines (polyvalent vaccines) or the need to vaccinate cats against rabies (unless required by state or local legislation) or administering FeLV to cats that are at low risk for infection. If we treat a cat with FIP, it should be treated in accordance with standard professional care, locality (rabies) and your practice. In short, treat the cat like any other cat, but have it cured first.
Questions about what will happen after the end of GS treatment
My cat has been with GS for several weeks and she seems to be doing well, but the titer of coronavirus antibodies is still high. Does that mean she's still sick? Should I be worried?
We do not see the coronavirus antibody titer value for you, so I cannot answer your question. However, we would expect it to take many months for permanent remission to occur. The fact that the titer is still high at this early stage does not worry us, but it may be something that should be monitored to catch a possible relapse. But we are optimistic. Symptoms indicate complete remission, and just as importantly, the cat has gained weight and figure in recent weeks. These were also favorable symptoms in our other cases, which did not suffer from a neurological disease. The high titer of the coronavirus also reflects the intense response of the immune system to the FIP virus. It is desirable for this titer to remain high for a while and then slowly return to a much lower titer.
What if your cat relapses after you stop taking GS? How do I find out? (Question about a neurological cat)
We hope that your cat will remain healthy after the end of treatment, but we must also prepare for a possible relapse. Relapses can occur within 1-84 days, based on our experience with other cats we have treated. The clinical signs of relapse will be evident in neurological cases, and will be essentially a recurrence of the same problems. They get a fever, the cat stops eating, becomes less active and the neurological symptoms she had before return. It is important to document what is happening. You can also measure her temperature every day for several weeks and then every other day until we reach day 84. During this period, it will be important to monitor the cat's level of activity and weight.
What thermometer should I use to measure the temperature of a cat?
I prefer digital rectal thermometers, which are characterized by high measurement speed. Do you measure temperature during rest and not after a certain time of physical activity? Temperatures may vary. One is higher, one is higher.
I noticed that after the GS was discontinued, the cat's temperature rose sharply. Does that mean the cat has relapsed?
Cats and other small animals are not as consistent in their systemic temperature as humans, and the fluctuations you see are not uncommon. The problem is that the more you worry, the more you measure the temperature and the more of these fluctuations you will see. For this reason, we are not very afraid of these fluctuations. It is much worse when temperatures are consistently higher than 39.5 ° C. It is important to note the overall condition of the cat, its appetite, activity levels and clinical signs. In short, fluctuations like these are fine unless they become permanent and are associated with loss of appetite and activity. If your cat is otherwise well and there is no evidence of a persistent fever, we recommend that the cat be only at home, where it is possible to protect it from unnecessary stress and monitor it closely.
Questions about laboratory results during or after GS treatment
My cat is being treated with GS and her lymphocyte count is high. That's all right?
The lymphocyte count is only slightly higher than normal, but in reality it is good. A low lymphocyte count would indicate that the infection is active and severe, while a high number would indicate that it elicits an immune response.
My cat has been on GS for several weeks and laboratory reports have increased creatine kinase and phosphorus. Is this a problem?
It doesn't have to mean anything if urea and creatinine are in the normal range. High phosphorus content may not mean anything yet. I recommend checking the values in a month.
We are concerned about the seemingly rapid increase in urea and creatinine in the blood. Do you have any other recommendations, or do you just need to supplement your fluids / diet and hope that the progression of kidney disease will slow down, as it is a young cat and it seems that the FIP has been successfully cured?
Yes, there is evidence of kidney damage and given the recent change and the fact that your cat is being treated this way, I think your cat may have suffered mild kidney damage. We only observed kidney damage that was milder than this in one of the more than 30 cats we treated for a total of 12-36 weeks and even at higher doses than you used. However, this type of medicine is known to be toxic to the kidneys in some people treated for HIV / AIDS or hepatitis C. This damage is reversible if you stop treatment early enough, and I assume you have already stopped treatment. If not, and you are at the end of 12 weeks or close, quit it. It does not reduce the chance of healing. Make sure the cat has access to water, and if her appetite is affected, feed her a moist diet that she likes with added water. Cats love wet food with juice and you can still mix a little extra water. There is a commercial and domestic diet for cats with kidney disease, but it is not very tasty and does not cure the kidneys, but rather protects the remaining kidney tissue. I would also make sure that your veterinarian does a urine test to find out what the specific gravity is - the lower it is, the greater the kidney damage. The more water cats drink and the more they urinate, the greater the kidney damage. It is necessary to determine whether the urine contains any signs of bacterial infection in the urine sediment or after cultivation - if they are found, antibiotics should be used immediately.
Questions regarding the oral form of GS
Some companies produce GS in tablet form. Is this form safe / effective?
Yes, at least one company in China also produces the oral form GS-441524, which it claims will work just like injections. This is not surprising, since the modifications required to convert injectable drugs into an oral form are well known. All drugs for HIV / AIDS and hepatitis C were also transformed into an oral form. However, like many others, you may find it more difficult to give tablets to cats than to inject. They usually adapt to the injections over a short period of time, but if they don't agree with the pills, it still gets worse and worse. Therefore, if you go this route, do not invest much in it until you are sure that you will be able to give the tablets to your cat.
Companies that make the oral form recommend splitting the dose and giving it twice a day. Why?
I do not know anything more about the oral form of GS, so I cannot provide a reliable answer to this question. However, there must be a reason why this Chinese manufacturer tells people to give GS twice a day and not once a day. Maybe it's because putting it all at once is too much of a burden for the cat system. It does not make sense to think that the medicine is excreted from the blood more quickly when given orally, which is another possible reason why they want to split the dose. It is important to me that these people are pushing hard for the oral form of the medicine, but have not provided any preliminary information on the success or tolerability, nor have any clinical trials been conducted.
Is there a risk of alternating injection and oral forms of GS?
It would probably not be appropriate to alternate these forms on a daily basis. But there is probably no problem with the transition from one form to another. The diluted drug in injection form usually contains 15-16.5 mg / ml and the dose for cats is 4 mg / kg, SC.
EN 
SK