Seems to me that the majority of folks who use Sudafed are doing so in order more easily equalize on decent. My take is that if you cannot easily and normally equalize on decent, then you need to "re-think" and probably abort that dive and figure out what the issue is.
For me the primary concern is a reverse squeeze on ascent if the Sudafed either wears off.....or your underlying condition that made it difficult in the first place get worse during the dive.
In over 50 years of diving I have only had one real bad reverse squeeze........ right under the boat in 15 ft. Every time I tried to ascend it felt like a no Novocain root canal... Lucky to have my 19cf pony and able to work it out....