Can dextromethorphan cause a false positive?
Score: 4.5/5 (1 votes) The over-the-counter antitussive medication dextromethorphan (DXM) can cause false-positive results for phencyclidine (PCP) upon urine drug screening (UDS). It is believed that DXM can also cause a false positive for opiates, presumably due to structural similarities.How long ...