I was recently prescribed some cheratussin, which contains a small amount of codeine. I took the recommended 1 teaspoon dose, and about an hour later had a strange reaction in my chest. It felt like a heart palpitation mixed with taking a deep breath. As quickly as it came, it was over. I have noticed a heart palpitation last time I used codeine as well, however it was just a fluttering sensation. Are these dangerous or anything I should worry about? I had an ecg last week and everything came back normal, so I dont believe I have any heart issues.. Also, I am unsure of whether this matters, but I do not have any palpitations on hydrocodone or oxycodone. I wonder if it could be a reaction to only codeine? Thanks for any input!