There have been recent reports of trace amounts of unexpected opiates found within tablets of prescription opiate medications. Three examples reported in the literature thus far are the finding of trace amounts of codeine in morphine tablets, the presence of small amounts of oxycodone in oxymorphone tablets, and small amounts of hydrocodone in oxycodone tablets. These unexpected drug findings are thought to be due to contaminants during the manufacturing of the pills. Note that these contaminated opiate tablets were created in legitimate, licensed, FDA/GMP-approved pharmaceutical manufacturing facilities. These contaminated tablets were not from illicit or clandestine labs.
This contamination issue will hopefully be resolved with time as manufacturers are now aware of the problem and are attempting to put in more stringent manufacturing processes.
Many commercial and private toxicology labs provide guidance on urine drug screen interpretation; some labs even have providers enter the patient's current medications as part of the urine testing order so that the lab can issue a customized interpretive report describing whether the patient's current testing is consistent (or inconsistent) with their current medications. While the contamination events described above could possibly explain an unexpected finding, these contamination possibilities are not usually considered when making interpretive reports. This is because not all tablets have these reported contaminants, and the reported concentrations of the contaminants have been small. However, a laboratorian who is asked to interpret findings should be aware of the possibility of contaminated tablets and stay up-to-date on literature describing issues like this.
