Like MummaSue said, we used to dissolve the tablets (in our case in some breast milk) and then give them to DD off a teaspoon. We tried doing it with a syringe for ages and it always just got stuck in there. Sometimes we'd even just tip the small container that we had dissolved it in straight into her mouth (she got used to it and would just open up in the end).

Good luck! Reflux sucks. DD was such a bad night sleeper until we got the pain of the reflux under control.