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These 15 Medications Can Cause a False Positive on Drug Tests

by Dr. Sharon Orrange on November 15, 2016 at 3:27 pm

We hear “false positive” as a defense from professional athletes all the time when it comes to drug screens—but unexpected  results on drug screens really do happen.

A urine drug screen tests for the presence of certain illegal drugs and prescription medications. You may be more likely to be tested when applying for a job than when playing professional sports, but you could also be affected by a false positive. Here are several common medications—prescription and over-the-counter—that you’ll want to be aware of as potential culprits for a false positive.

  1. Amitriptyline. This is a tricyclic antidepressant used for chronic pain, neuropathy (nerve pain), depression, and migraine prevention. Amitriptyline may lead to a false positive urine test for the hallucinogenic drug LSD (lysergic acid diethylamide).
  2. Bupropion (generic Wellbutrin). Used as an antidepressant, for weight loss, and smoking cessation, bupropion may lead to a positive screen for amphetamine, methamphetamine, and LSD.
  3. Dextromethorphan. Found in Robitussin, Delsym and other over-the-counter cough suppressants. If you’ve taken a medication with dextromethorphan in it, your drug screen may be positive for opiates and PCP (phencyclidine).
  4. Diltiazem (Cardizem) is used for hypertension (high blood pressure) or to slow your heart rate if you have atrial fibrillation. If you’re taking diltiazem your urine drug screen may test as a false positive for LSD.
  5. Diphenhydramine (Benadryl). Many over the counter remedies contain diphenhydramine, an antihistamine also used as a sleep aid, including Tylenol PM and Advil PM. If you’ve taken these, you could test positive for methadone or PCP.
  6. Ibuprofen and naproxen (Advil/Motrin and Aleve). Two very common over the counter anti-inflammatory pain medications. If you’ve taken either of these, your urine screen may test positive for barbiturates, THC (cannabinoid), and PCP.
  7. Metformin (Glucophage). The most commonly prescribed oral medication for diabetes, taking Metformin may result in a positive test for amphetamine or methamphetamine.
  8. Fluoxetine (Prozac) and trazodone. Both are used to treat depression and may result in false positive tests for amphetamine or methamphetamine and LSD.
  9. Pseudoephedrine (Sudafed). Used for sinus and nasal congestion, Sudafed—as many of you already know—may result in a false positive test for amphetamine or methamphetamine.
  10. Labetalol (Trandate) is both an alpha and beta blocker used for blood pressure control. If you’ve taken labetalol you could have a false positive for amphetamine or methamphetamine and LSD.
  11. Methylphenidate (Ritalin). Used for the treatment of ADHD, this Ritalin is a well-known cause of false positive tests for both amphetamine or methamphetamine and LSD.
  12. Doxylamine, found in Unisom and other over the counter sleep aids (similar to diphenhydramine), may cause a false positive on a drug test for methadone, opiates, and PCP.
  13. Sertraline (Zoloft) is an antidepressant and if you’ve taken it, you may test positive for benzodiazepines and LSD.
  14. Tramadol (Ultram) is a non-opioid medication used for pain. Your screen could come up positive for PCP if you’ve taken it recently.
  15. Quetiapine (Seroquel) is an atypical antidepressant/antipsychotic used for bipolar disorder, depression, and schizophrenia. Your drug test may show up positive for methadone if you are taking quetiapine.

Hope this helps.

Dr O.


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