|I have good news and bad new about your terrier Mr. Schrödinger.|
I get good news and bad news from time to time.
The bad news is that a friend's 8-year old terrier is very sick due to poisoning from a Trifexis flea and worm pill which has lead to the start of liver failure. The dog may yet come out of it (the kidneys are still working), but I have warned folks about this particular flea and tick treatment before. It has already killed thousands of dogs. Stay away from it. Use what you want, but I am happy with a pyrethrin-based shampoo. As a general rule of thumb, use outside drugs for outside bugs and inside drugs for inside bugs.
The good news is that a reader writes to say that her heart worm-infected German Shepherd is now clear and healthy after 3 cycles of the Doxycycline and many doses of Ivermectin. She writes that she got the Doxycycline off-shore as I suggested, and that the Ivermectin was dirt cheap following my directions. "The blood tests were the most expensive part of the whole deal."