Zantac users?

Holy cow - Sam has been napping in his crib for just over an hour now!! He has woken up and fussed several times, but put himself back to sleep.

The only thing that is different is that I gave him his Zantac after he last ate instead of before. Could that be it?

I'm going to ask the doctor later today, but I'm curious to know if anyone else has noticed a difference.