@Emma-louise thank you
No problem my Dr told me it was a rare cross contamination but I'm unsure if that's the case but lactose usually doesn't contain any milk proteins as it's the sugars 😊
Lactose is different from cow's milk protein so should be ok on that front. You'd only have to avoid lactose if baby is lactose intolerant.
My little girl is cmpa and had lactulose with no problems
So most babies are fine with it as if you're using omerprazle that usually has lactose in it too My little girl however wasn't able to have lactulose and come out in a rash everytime we used it so now have pedeactric movicol