I can't imagine how a tiny amount of sorbitol in your nose is getting to the colon or causing large volumes of gas.People aren't allergic to sorbitol so it isn't one that the longer it is there the worse it is.The reaction to sorbitol is in the colon where it gets turned into gas and can pull water into the colon. One molecule of sorbitol can only do so much. It isn't where one molecule cause hundreds of other reactions. It forms a couple of molecules of gas or holds and extra molecule or two of water in the stool.If anything it should make you less constipated, not way more constipated.The breathing problems at night can be enough to set off IBS issues. Also if you have any allergies to pollen the last couple weeks (at least here) have been horrendous for pollen counts and that could be messing you up all by itself. I'd be more likely to wonder if you react to the drug part, rather than the inert ingredients part (and usually even the highest amount of the inert ingredients is much less than the active, they are two different lists. And like I said with as bad as the pollen has been around here this year everyone, even ones on good allergy control, and even people without allergies, all seem to have problems just from the amount of junk in the air.