I was told at the vet that this is a safe treatment. Did your Lurcher react quickly, or did it build up over time? The care leaflet in the box does state that a small number of reports have been received of sudden death.
I think it's a risk I am willing to take, although of course I'll be watching her like a hawk, and going back to the vets for regular monitoring. She has lost muscle and fur, is so hungry all the time that she cries if I won't let her try to scrape chewing gum off the pavement, wakes in the middle of the night distressed and needing food, has become an anxious little dog when awake, but gets worn out very quickly, even on very short walks, and then needs to sleep for an age. She has to be helped or carried up and down stairs (and we have a lot in our house), and has tumbled all the way down on many occasions. She has had two bouts of her back legs folding under her, and therefore being unable to even sit up unsupported. She and I were both very distressed when that happened.
It's a quality of life decision, and I think hers will be improved with treatment. I hope I don't have to eat my words. I feel she can't go on for any longer as she is.