Primidone might cause anxiety, agitation, or depression during the first few therapeutic sessions, along with ataxia and sedation. Polyuria, polydipsia, polyphagia, liver changes, thrombocytopenia, neutropenia, and anemia are potential side effects as well, and should be mentioned to your veterinarian. On rare occurrences, anemia might occur.
For cats, ataxia, lethargy, polydipsia, polyuria, polyphagia, and weight gain have all been reported as side effects of Primidone. In some rare cases, immune mediated reactions and bone marrow hypoplasia can occur.