Cough
"I was prescribed this medicine in the ER when I was diagnosed with Bronchitis.  The very first thing the doctor said with this medication is do not drive.  I totally agree, the medicine is wonderful it pretty much got rid of the cough, and helped clear up my head congestion.  I would have to say that the worst side effect is that it makes you feel very drowsy and sleepy, like you are under the influence of alcohol."