Feedback on False Positives from Drug Testing, page 121

False Positives Forum

This forum is intended to help those who Do NOT Abuse Drugs. We do NOT support the illegal use of any substance. If you have experience with false positives, share your experience. What would you tell someone about drug testing and false positives? Please remember that we do not give medical or legal advice.

Subj: Alprazolam
Date: 2/16/2011
I am taking Alprazolam 0.5 mg and tested positive (swab test) for Oxazepam and Temazepam instead. How is this possible? I am also taking Oxycodone 80 mg but tested negative on opiates. Please help


AskDocWeb: Alprazolam contains benzodiazepine, which is metabolized into Oxazepam by the body. Oxazepam is a common metabolite of many other benzodiazepines. Chlorazepate, chlordiazepoxide, diazepam, and temazepam are all metabolized into oxazepam. Most urine drug screens detect all the benzodiazepine drugs that are metabolized in the body to oxazepam, nordiazepam, or temazepam.

Subj: Phendintrazine?
Date: 2/16/2011
Will the drug phendintrazine cause a false positive in a drug screen test and show positive result for methamphetamine?


AskDocWeb: Phendintrazine is not in our database. The closest we could find is Phendimetrazine, which has shown up as a false positive for amphetamines and ecstasy (Ref: 3, 11).

Subj: Positive for marijuana
Date: 2/16/2011
Please let me know if any of these medications will test positive for thc marijuana, spironolactone, pacerone, carvedilol, sulindac, dilantin, amitripyline, lisinopril, cycobenzapr, plavix, klor-con, liptor.


AskDocWeb: Dilantin has shown up as false positives for barbiturates but not marijuana. Likewise Amitriptyline has shown up as a false positive for LSD but not for marijuana. The other drugs are not on the list.

Subj: Tested positive for cocaine
Date: 2/17/2011
My husband tested positive for cocaine at probation he does not do drugs but does take Imitrex, hydrocodone and percocet for headaches due to a broken skull. Could these have caused a false positive?


AskDocWeb: Percocet will test positive (not false) for opiates (Reference 3 and 20), which is why it is important to furnish the people doing the test a list of the prescription drugs being taken. Ideally, the prescriptions should be shown before the test.

Subj: Seroquel (quetiapine)
Date: 2/17/2011 states that Seroquel (quetiapine) may produce false positives for amphetamines.


AskDocWeb: Thanks Michael, good catch.

Subj: Bactrim
Date: 2/18/2011
I took Bactrim and it caused a false negative in my urine test for BENZOS. I have not taken benzos in god knows how long. I took a lab test the very next which came out negative for BENZOS, however it did come up positive that Bactrim was in my system. SO obvioulsy Bactrim Did Cause a false Positive in a standarded non lab Test. Be careful.


Subj: Lamictal
Date: 2/18/2011
Actually, yes, Lamictal can cause a false positive result in a drug screen. I had a drug screen recently and in fact, there was a positive in the PCP. The test was done because we are working to be licensed for adoption. I don’t do drugs, have never done drugs. I am a 41 year old mother of 3 with a husband, kids and of course a job. I have no time to even think about doing anything related to drugs. There are quite a number of people reporting that they had the same result. For some reason, I can’t post a link here, but check out the redwoodtoxicology under documents, the file is called cross_reactions.pdf. Hope this helps.


AskDocWeb: (answer revised 6/30/2011) We found the file you referenced but Lamictal is not on that list. However, we found another source that says Lamitcal might test positive for PCP. Anyway that is such a good list that we added it to the references. Thanks Bella!

Subj: Positive for meth?
Date: 2/18/2011
can you test positive for meth. anphed. with Ibuprofen. and also what about fluoxitine.


AskDocWeb: The only thing Ibuprofen has shown up for on urine tests is THC. Fluoxitine has not shown up on urine drug tests at all.

Subj: Risk of false positives
Date: 2/18/2011
Will I hae the risk of false positives showing up in my urine test being taking Propranotol 10mg. as well applying Lidoderm{Lidocaine} patches to my spinal areas of my back injury?


AskDocWeb: Those drugs have not been reported to show up on urine drug tests for drugs of abuse.

Subj: Tizanidine
Date: 2/18/2011
What are the false positives I may have while taking Tizanidine in my urine tests that might show up?


AskDocWeb: There are no reports of Tizanidine causing any problems on urine drug tests.

Subj: False positive for benzos?
Date: 2/18/2011
I am on Celexa, Buspar, Abilify, Tramadol, Valtrex and Doxepin and take Excedrin regularly. Can any of these cause a false positive for benzos?


AskDocWeb: None of those have cause a false positive result for benzos on a urine drug test.

Subj: The best thing you can do
Date: 2/19/2011
Hi everyone- …There really is nothing worse than a false positive test result, especially if your being screened for a job, probation, court cases, or your doctor. I know that everyone metabolizes drugs differently, and the smallest thing could throw off a false-positive (Personally, Im not familiar with false negatives)..I tested positive for amphetamines and opiates once, and lost my doctors trust and medicine because of it! It turns out, I ate a bagel that contained poppy seeds, causing the false read for opiates, and Zantac (an over-the-counter heartburn medicine) that made me test positive for amphetamines. If this happens, the best thing you can do is to go to the hospital and have your blood drawn RIGHT AWAY to clear up the mess. GNC makes an expensive drink that will flush out your entire system, if your worried about what might come up. False positives happen more than people think, so protect yourself and dont give in…


Subj: Tested positive for phenobarbital
Date: 2/19/2011
I recently tested positive for phenobarbital on a drug screen at work. Amazed the hell out of me. I only use drugs prescribed by my doctor. I take morphine sulfate er 15mg, meloxicam 15mg, amlodipine besylate 10mg, omeprazole 20mg, simvastatin 40mg, and prochlorperazine 10mg. About two days prior to my test I was given and injection of phenagren vc for extreme nausea and abdominal cramps. Would this coctail possibly be the culprit?


AskDocWeb: We have no explanation for your test results however, many states have regulations covering drug testing in the workplace. For example Phenobarbital is not a substance that Oklahoma employers are permitted to test for under state regulations. (See Standards for Workplace Drug and Alcohol Testing Act, 40 Okla. Stat. ยงยง 551-565)

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