Therapeutic use of bupropion appears to be the most frequent cause of false positive urine drug screens for amphetamines in our population. Question: What can cause a false positive urine drug screening for amphetamine ? mg of bupropion daily and testing falsely positive for amphetamines. Find out which drugs can potentially cause a false positive drug test including bupropion (Aplenzin, Forfivo XL, Wellbutrin XL, Zyban). Continue Reading. While urine drug screenings are valuable tools in pain management, they have limitations, including the potential for false positives. This review focuses on cases where the cause of a false positive is identified. False-positive tests for benzodiazepines have also been reported and are likely due to the 8-hydroxy-efavirenz major metabolite. False-positive interferences of common urine drug screen immunoassays: a review. Massive venlafaxine overdose resulted in a false positive Abbott Link urine immunoassay for phencyclidine.