If you worry that the Tagament will give you D, I would suggest you not take it until you see if the Colestid can get you regular. Mind you, I don't know anything about planter's warts, but I don't think it will make things worse to go without treating it for a while. I always try to err to protecting my stomach over treating anything else unless whatever else I have is actually worse than my stomach. But you can always just call your dr's office and ask them if there is any problem with delaying taking the tagament until you get your guts settled down somewhat.
I have taken tagament before, on an as-needed basis for regualr heartburn, but I don't recall that it ever bothered me. But being on it all the time may do something.