Drug tests, while they can be effective at detecting illegal drug use, can also falsely detect several kinds of prescription and over the counter medications as if they were illegal substances. These false positives can occur because drug tests are not able to tell the difference between illegal drugs and medications. A false positive means that your drug test has detected drug use when you have not taken any illegal drugs.
Ibuprofen (Motrin and Advil) Naproxen (Aleve) can show up on a drug test, giving you a false positive. These very commonly taken anti-inflammatory medications that can show up on a urine drug screen as marijuana or barbiturates. Ibuprofen can also be screened as PCP on a urine drug test.
Metformin is a commonly prescribed medication to treat diabetes. However, during a drug screen, this may be detected like amphetamine or methamphetamine. Diltiazem, used to treat high blood pressure or slow down your heart rate, can show up falsely in a urine drug test as LSD.
Some of the most common antidepressants can mimic illegal drugs on drug tests. Antidepressants like Serequel, Wellbutrin, and Zoloft may show up when you are tested for drugs because the test may think they are methadone, LSD, or amphetamine or methamphetamine.
Many of us reach for Robitussin or other over the counter cough medicine, but if you have a drug test coming up, these cough suppressants can show as if you have used PCP or opiates.
Benadryl, Tylenol PM, and Advil PM are readily available over the counter antihistamines that can also produce false positives on a drug test. If you have ingested these recently before a drug test, you may incorrectly test positive for opiates, PCP, and methadone.
If you have taken any of these types of medications, it is best to tell the technician giving you your drug test upfront about them. Drug tests are designed to do just that – detect drugs. Since they are not able to determine the difference between prescriptions or over the counter medications and illegal drugs, this shortcoming can cause you to fail a drug test. False positives on drug tests can be incredibly distressing and have negative outcomes for you, so be honest about any medications you have recently used once your test time arrives.