Similac Alimentum??

Question

My baby is 3 weeks old. She just got switched to similac Alimentum because the doctor thinks she may have a lactose allergy due to having blood in her stool. Since being on the similac Alimentum she is eating less and spitting up way way more. I’m worried about dehydration. We have a doctors appointment in about an hour but I was wondering if this has happened to anyone?

Answer

My 5 month old girl is on it for the exact same reason, she's been on it for about three months now. She definitely doesn't eat as much, she went from 4oz to 2 1/2oz at the time but she is still gaining weight so the ped wasn't very concerned. She has an appointment on Wednesday where I'll be bringing it up again (different ped) to see what they think. I didn't notice her spitting up any more than usual, it just takes a bit for their system to get used to it

Answer

It’s an adjustment. My doctor made us stick it out for 2 weeks and he is just fine now! 6 months old.

Answer

My son is on Nutramigen for a milk allergy, sounds similar to what your LO is on. His spit up was craazzzyyyy for the first two weeks then it chilled out. He still spits up, but not nearly as much. 
It may just take a but for you LOs system to get the hang of the formula. Glad you made an appointment! 
I hope the best for you and your LO!