What prescription drugs will give a false positive for heroin in a drug test?

First, Diabetes, liver disease, kidney infection and kidney disease all will throw false positives for opiates--so if you fail a drug test because of one of those and you didn't know you had them, you should be glad. Some antibiotics can too, but all the antibiotics that do it have names ending in "oxacin." Also, anything containing Dextromethorphan (this is the active ingredient in many cough syrups) and poppy seeds can throw false positive for opiates.