My 9 yr old son is asthmatic and has has a pretty bad caugh. He was prescribed Promethazine/Codeine Syrup for a cold a few months ago when he had the same exact cold. This time he developed a severe breathing problem while he was sleeping after taking this medecine for about a week and a half. I took him to the er and the doctor there told me that a child especially if he's asthmatic should never take this medication. Could the cause of this new breathing problem were he gasps for air for a few seconds be the cause?