Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am sorry that you have been waiting for a response, but your requested expert isn't online which delayed your question coming up on the list for all to answer. I would like to help if you are still interested in an opinion.
I understand that you are worried about triggering a relapse of IMHA with the use of Cefpodoxime. It is always a balance using any medication, weighing the benefits of a medication with possible side effects.
Was her original bout triggered by antibiotic use? If so was it an antibiotic in the Cephalosporin family?
Certainly if her previous bout was triggered by an antibiotic, especially one in the Cephalosporin family then we do need to be concerned.
However if her previous but was not related to a Cephalosporin antibiotic, and especially if it wasn't related to an antibiotic at all, then I am more comfortable.
If she has a urinary tract infection she needs an antibiotic, and if it is an infection that is responsive to Cefpodoxime then the benefits of its use outweigh the risks of a reaction.
While it is true that Cefpodoxime can cause a false positive Coomb's test (which is a test that measures red cells sticking together and can point toward IMHA) that does not mean it is more likely to cause IMHA compared to other antibiotics. Sulfa and penicillin antibiotics are actually more likely to trigger IMHA compared to cephalosporins.
I wouldn't use any medication for a lengthy period in your girl if we can help it. But I suspect that your veterinarian carefully weighed the pros and cons and took into your girl's history and felt that the use of this antibiotic was more likely to be beneficial than harmful.
Please let me know if you have any further questions.