texan:
I agree with Nancy. I had trouble with ketitofin pills & the only reason could think of was the corn starch inactive ingrediant. Both corn starch which a lot of the generic drugs use as a filler & pregelatinized starch both are high in sulfites due to the process to make them. This was my reason to switch from zyflo to singulair, also to use regular zrytec not the generic. Allegra has the pregelatinized starch as a filler. I watch both these in all my foods & I seem a little better with my skin symptoms. All I know is I can now take liquid benedryl & tylenol that don't have the fillers & they help when symptoms act up. The other thing we all get a lot of coincidence symptoms that just happen at the time we take meds. These should be explored multiple times to make sure there is a direct correlationship before the meds are blamed for the symptoms. Once again my opinion from 6 years of experience.
mikev

Thanks guys, will check those ingredients.  I have a super sensitive tummy and have to take zantac and prilosec to keep it under control.  I have tried Allegra twice now and same problem each time.  Oddly enough, my daughter had to switch from Allegra to Zyrtec for same reason.  I am going to give singulair one more go though....BTW, I could not take Elmiron for IC for same reason, gave me horrid GERD the whole time I took it, after a year of GERD gave it up!  Dissappointing at the time give the nature of IC.  Will see about fillers...I know food additives, for example, glutamates, are not my friends...Thanks for the tip, will see!

Kristi,  

I got my allergist to give me some children's Singulair chewables to try to begin with.  I could cut them in tiny pieces.  Found out I can't tolerate Singulair, though.  Also, some people might no be able to tolerate the extra ingredients (flavoring etc) in the chewables.