Re: Common to give children Prevacid for reflux?
I'm not sure which "serious" side effects you're referring to, but Prevacid is generally a very safe medication.
The only two listed side effects in the prescribing information, that were more common for Prevacid than placebo, are abdominal pain and diarrhea. You might keep in mind that they list every side effect, even if it is only reported by one person or was reported by more people taking a placebo than the prescribed medication.
It's not unusual for Prevacid to be prescribed for children as young as 2. Obviously if you're concerned, you should talk to your doctor about other options but all of the drugs in the same class as Prevacid have similar side effects (and are generally very safe).