I too was prescribed terbinafine for fungal nails, and after seven weeks had to stop them it due to excessive watery diarrhea, unrelenting. I ended up losing 25 pounds and having a colonoscopy with a diagnosis of Lymphocytic colitis.
It's now over a year since this started and I have just had my first normal BM. I am being treated at present with Asacol 4.8mgs daily and just started a nine week course of Budenfalk which is what is helping most. Wish I had never taken terbinafine. I would love to turn the clock back and stick with my fungal nails rather than have this colitis.