Zantac side effect?

My daughter had reflux pretty badly as a baby, but seemed to have grown out of it. She’s almost 2 now and it came back with a vengeance a few months ago. It got to the point she was hardly eating anything, emptying her tummy, and losing weight. We’ve been consulting with an amazing GI doctor and ruling things out. At this point we’re on our second medicine we’re trying, which is Zantac syrup. It seems to be working with her little body much better than the first one we tried. However, the last couple weeks her sleep has been all over the place. She’s been very restless at bedtime, even on days she totally skips naps and I know she’s exhausted. She’s a pretty good sleeper overall, but she’s a toddler so I’m never surprised by any phases of less sleep lol. I know that’s normal.

All that to basically ask, does anyone have experience with Zantac in their littles and it causing any sleep problems? Because of the timing and that this has been going on at the same time, I’m wondering if it’s just coincidence or possibly a side effect. Was hoping to see if that’s a possibility from others who have used Zantac before mentioning it to the GI doctor. I don’t want to make it a thing if it’s not, especially since this medicine seems to be helping her overall.

Thanks! 💕