Any vets/vet pharmacist types about?

[IdaDown]

So, crusty dog has leishmaniasis. Been with us for 3 years.
Titre has gone up from 1/200 to 1/4000 over this period.
Bloods are up/down. March was particularly bad, we nearly lost him ( kidneys).

Currently on
allopurinol - daily
domperidone - every 3 months
Milteforan - 2 courses in past 18mths

Last Milteforan course finished just over a month ago. Post Milteforan blood works were good (for crusty dog - just outside of normal ranges for urea/creatinine/calcium etc...)

However, he's loosing hair again especially along legs and around his eyes - classic leish and I'm concerned he's not responding to treatment.

Crusty dog was on (first 18mths) a Greek allopurinol tablet called Zylapour. I'm clutching at straws here but I think he started to go down when we moved from Zyl to generic. I've looked on line to find the ingredients of the Zyl but have had no luck.

Does anyone have access to drug components or is it trade secret? I'm just wondering as leish is a common med disease, perhaps the Zyl/allopurinol tablet is slightly different to a generic allopurinol?