Just wnated to let you know I see yoru post and have no idea.
I mean, I can only guess it is safe isnce Ellie has liver issues and I asked to try lactulose. Her vet knew there was a history of pancreatitis and prescribed it for me anyway. I never ended up filling it though. This was her regular vet though, not an internist.
I always have questions about if things are okay for pancreatitis and liver compromised patients and I think it depends on the individual case. I can't find anything about it on Google. Did the vet say it would irritate his pancreas?