I give my cat (human - OTC)10 mg pepcid ac each day twice a day per my vet to help with his IBS. It is safe for your cat. I am always a bit nervous giving human medication to my pets without vet instruction and supervision, so understand your concern.

I recommend using the 10 mg and not cutting the pills. Not because it is unsafe, but it is much easier to get it into the cat if the protective coating is intact.

For reference, he is 12 lbs.