When I went to the doctor for my horrible cold/respiratory infection/possible pneumonia my doctor gave me some free samples of Deconex DM. They are sustained-release tablets and each contains: 900mg of gualfenesin, 30mg phenylephrine hci, and 30mg dextromethorphan HBr. They seem to help ok. The make my coughs more productive and less frequent and help stop sinus drainage, but the coughing can still really hurt and make my head hurt. I take one pill every 6 hours. I think this pill is better than the over the counter decongestants I was taking, but this is not a miracle pill. I have to drink a lot of water with these pills or else they make me feel dehydrated. I really have not noticed any side effects- other than they dry out my nose a little but not uncomfortably so. As miserable as I have been with the coughing and rattling chest, a dried out nose is nothing. I probably have taken more medication these past 3 weeks than I have in the past 3 years! The one nit-picky complaint I do have of this pill is that it is huge and uncoated. My throat has been sore and irritated so sometimes forcing this down is hard work. I wish they would at least put a gel coating on the pill.