My 4yr old suffers from acid reflux. she takes prevacid (lansoprazole) daily but still complains of belly discomfort at night? why is this?

See below: First, laying down flat worsens reflux, so put some books under the head of her mattress to elevate it a little.Also, it helps to have a few hours to digest dinner before going to bed.And part of this pattern may be that during the day there are things going on that distract her from her belly symptoms, while at night in bed there's nothing to distract her.Her doctor can check for other causes.

Various reasons: The medicine may not be working 100%. She may have an emotional reason (like attention) to complain at night. She may be constipated or have a mild food allergy. A visit with your pediatrician will help a lot. A more detailed history will help.