Spitting up Medicine

I posted this message right before the site went down, so if there were any replies, I didn’t get them! So I’m posting again:
My son has a problem with spitting up his reflux meds. I don’t know how much he has spit up, so I don’t dare give him more medicine, but then he has worse problems with the reflux without the meds. He does really well if I give it to him when he’s asleep (he takes meds through his G-tube) but he isn’t always sleeping when he needs to take his medicine. I also try to keep him upright for awhile after he takes it.
Is there anything I can do to help him keep it down?? Anyone else have this problem.