going casein free - question about lactulose

[MommyUpNorth]

DS has started the first part of the gf/cf diet on Monday. We've tried to remove all dairy, and it's going better than I thought!

Anyway, one of the medications he is on is lactulose. I think perhaps I'm reading too many books on the diet and the simple breakdown says to remove anything with the 'lact' in it to be safe. So would lactulose need to go, or not as this is actually not containing the casein?? (getting more confused the more I read!)

I'm going to remove a portion of one medication at a time every 2 weeks so we can see the clear effects of what is happening. Plus I'm charting it all so I know where we stand with behaviours & poo! So I don't want to remove it yet if I don't have to iyswim...