I hope you found serrapeptase by now. I found it when I sort of "fell on it" at vitamin shoppe. There are actually 2 others that have similar effects. I bought them but have yet to try them.
I think if you look for serrapeptase on Amazon the others will show up in the search. One of them has been found to be much more powerful than the serrapeptase. Sorry I didn't save the research.
I did tremendous research on fenben but although I saw lots of stuff stating that it had nuerological effects I never found a medical journal that said exactly what that effect was.
Veterinarian journals caution about using fenben on cats for the same reason but still no statement of what the effect is.
It is the only thing that works on my cat.
The positive thing I see is that fenben must cross the blood brain barrier or it wouldn't cause effects to the brain. I've also tried Oxibendazole because the dosage is so much lower but I didn't think it worked well.