Can Mucinex (Guaifenesin) cause gastritis or irritate existing gastritis/ulcer?

[nhagerty74]

Can Mucinex (Guaifenesin) cause gastritis or irritate existing gastritis/ulcer?  I was taking Mucinex for 5 days, 400mg once a day, and now my stomach is bothering me (burning pain).  I have suffered from gastritis and a gastric ulcer in the past.  Could this medication cause or aggravate those problems?  It was actually helping my sinuses to drain, but now I'm afraid to take it. :(

[oldenoughtoknowstuff]

The stomach protects itself from the acid that digests food with a coating of mucus.  If the guaifenesin breaks up sinus mucus, it stands to reason that it will break up the mucus in your stomach.  I got a wicked case of gastritis from mucinex.  I deduced this was the reason why.  

[Dr Santos]

Hi,
Side effects  of Mucinex or Guiaffenesin include gastrointestinal symptoms like diarrhea, nausea, vomiting and stomach pain. Dizziness, headache and rash may also be observed. It is best that you discuss this with your doctor for proper management. Take care and do keep us posted.