Mycophenolate Warning

Our 12-year-old, male, neutered, roughly 9 lb, toy poodle was diagnosed with IMHA around Halloween 2018 with a PCV of 8% and is now recovering, his PCV recently measured at 46%. In late November, after three transfusions and much heartache, he appeared to be failing to respond to the meds (prednisone, cyclosporine, and mycophenolate). We were told by multiple doctors that there was nothing they could do. But it turned out that mycophenolate was CAUSING anemia and preventing recovery. Since discontinuing mycophenolate in late November, right after his third transfusion which had brought him up to 25%, his PCV has steadily risen, entering the normal range a couple of weeks later, and, to our surprise, continuing to rise even as he’s being weaned off prednisone. Here’s a timeline:

10/31/18: PCV 8%, receives first transfusion
11/1/18: PCV 25%
11/2/18: PCV 25%, starts on prednisone and cyclosporine, comes home
11/7/18: PCV 23%, doc adds mycophenolate
11/14/18: PCV 18%, has some kind of respiratory infection/discharging from nose, prescribed antibiotic baytril, receives second transfusion, immediate PCV reading is 32%
11/19/18: PCV 23%
11/24/18: PCV 14%, emergency doc says prognosis is poor/not responding to drugs, receives third transfusion
11/25/18: We discontinue mycophenolate on our own after reading that anemia is a common and severe side effect of the drug in humans
11/26/18: PCV 25%, doc says there’s nothing she can do except more transfusions, recommends we not discontinue mycophenolate, but we insist and she agrees to let us try
11/30/18: PCV 26%, doc is apologetic
12/7/18: PCV 32%
12/31/18: Prednisone reduced from 10mg/day to 7.5mg/day
1/4/19: PCV 37%
1/14/19: PCV 43%
1/21/19: Prednisone reduced from 7.5mg/day to 6.25mg/day
2/7/19: PCV 46%
2/8/19: Cyclosporine reduced by half from original dose
2/11/19: Prednisone reduced from 6.25mg/day to 5mg/day

In retrospect, we believe that his first week going from a PCV of 25% right after transfusion to 23% 7.5 days later, while just starting on drugs which take a little time to work, should have been viewed as a success and mycophenolate should never have been added. I know mycophenolate works for some IMHA dogs, but in our dog’s case, it would have killed him if we hadn’t been able to afford a couple of more transfusions.

We will soon get a new PCV reading to see how he’s responding to the significant 2/8 cyclosporine cut and the ongoing slow prednisone wean. We’re reducing the prednisone very slowly to try and prevent relapse (3 week intervals, roughly 20-25% reductions from previous dose).

He had put on weight going from under 8.5 lbs to near 10, but he appears to be slimming down of late and seems happy and energetic. He’s also less and less food-focused as the prednisone is reduced.

I wish every dog and dog owner suffering with this mystifying and heart-wrenching condition the best of luck.