In general you should see an effect within the first couple of days with the full effect by two weeks. 

Is this the first medication your baby is on for reflux? I'm asking because lately there's been an issue with getting Prevacid and a lot of babies are switching to other medications.

If you have noticed an improvement but not enough then it's possible the dosage may need to be increased. If you are not noticing any improvement then it's time to go back to your doctor with this information. Doctors do medication trials to confirm the diagnosis. If it didn't work then that's helpful information for your baby's doctor to know and then help your baby.

Stephanie