Just looked this drug up on the internet and all I can find is that is used to abort unwanted pregnancies in dogs.

My girl has been attending my vet with amongst other things a "suspected" pyometra (not confirmed by scan) and this is the drug they have been using to treat her.  Does anyone know of any side effects of Alizin? 

I think its a prostaglandin drug and it works by contracting the uterus to expell its contents. So I suppose its quite painful.
Many vets will use this as an alternative to speying, particularly if the bitch is a valuble breeding bitch. I do know some one who had this drug instead of speying with a pyo and a couple of weeks later had to have the surgery anyway.

Joan, I had a old Dane who had suspect pyo, but they didnt want to put her under a GA, I dont think she would had made it anyhow, anyhow they treated her with this drug and anti b's, she went on 6mths to her next season, and it flared up again, unfortunatley we decided to pts, she was 11years old, but it did help Rhea, with no side effects.