So my LO has been on the target brand of Simlac Sensitive since he was about 1 month old. He initially was on Similac Advance because that's what they gave him in the NICU but he had constant gas a diarrhea, so I switched him to UP & UP lactose sensitive.
He pukes no stop so I am going to be switching him to the UP & UP equivalent of the Enfamil Gentlease. Should I mix his current formula with the new (we have about 1//2 can left of the lactose sensitive)? Or should I just switch him cold turkey?
Re: Switching formula
How long has the puking been going on?
Usually a switch like what you're talking about will not really have an effect on a symptom that severe. Switching from Enfamil to Similac "regular" brands (like Sensitive / Gentlease) is more for smaller issues, like gassiness/fussiness.
What does your ped say? This far along it could be a milk/soy protein allergy or reflux - all of which would require a more specialized formula to make any type of difference.
I would not switch cold turkey, personally. I'd do at least half n half for a few days, but my LO's tummy is veryyyy sensitive.