Reglan can cause the side effect tardive dyskinesia if you want to google yourself into scary doom. google it. It is a neuro side effect that often DOESN'T GO AWAY. Yes we had to put my son on it, and very occasionally my son still will take it (and I mean once every couple of months one dose) but if you don't have to take it long term..you shouldn't. Also never ever ever take it with alcohol..as alcohol will intensify the active ingredients in it...making you even more likely to have neuro side effects from it.
And if you start having tremors, hand shaking, involuntary movements of the tongue, literally stop taking the drug and never ever take it again. That is the beginning symptoms of tardive dyskinesia
H2 blockers are considered safe long term.
PPI's when they first came out...there was concern they may cause long term damage. there is still concern it may block absorption of calcium..but that is typical concern for children, not as much of an concern for adults..normally what doctors look at is the benefits outweigh the minimal disadvantages it could cause.