Cough and Nasal Congestion
"First time ever taking Mucinex D! Took two pills as directed and it did clear some sinus pressure during the day.  Following directions 12 hours later and took my two pills dose at 10pm. I&#039;ve been clear in my sinus, but tossing and turning all night! It is now 2:05am! insomnia was a side effect so did not read about until now, since I can&#039;t sleep! So, yes, Mucinex D does work, just do not take at night as directed. Unless you need to be awake while others sleep, in which case, this will definitely keep you up all alert!"