Questions about False Positives in Drug Testing, page 228

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 this forum is not for medical or legal advice.

My husband takes 40mg of fluoxetine once a day and keeps failing his drug tests for benzos is this common or rare???


AskDocWeb: Fluoxetine has not been documented to cause a false positive for benzos although it has shown up as amphetamine and LSD on urine drug tests.

Is zanaflex 2mg tablets a narcotic and can it make u fail a drug screen? Can u give me some information on this medication my dr preescribed it to me for pain due to m.s.


AskDocWeb: Zanaflex is a brand name for Tizanidine. This is part of a group of drugs called skeletal muscle relaxants, which are used to decrease muscle cramps and spasms. It has not been documented to show up as a false positive on urine drug tests for drugs of abuse.

Nursing student tested positive for benzos
I am a nursing student and just tested positive for benzo. I am a 20 year Crohn’s patient and take St. John’s wort and valerean root (anxiety: GI dr stated ok to take unless I experience negative s/e), prescription lortab 7.5 (1 q 4-6 hrs PRN), prescription prednisone (20mg q day), prescription Imuran (150mg q day), folic acid, calcium with vit D, acidophilus (BID), Zegrid OTC, vit C, benadryl (4-6 q day), and phenergan 25mg (2-4 PRN, nausea).

I have never taken any benzos. What has caused the positive test and how can I or can I dispute this? I know as a nursing student, the lines are stark and stiff. As a nurse, you get the choice to rehab, retest, or lose your license. As a student, it appears that there is no option with a positive, even if it’s possibly a false positive. Please help me. I have spent nearly 3 years dedicated to becoming a nurse and only have 16 weeks left! This could ruin my chances of becoming a nurse forever!


AskDocWeb: Valerian root and its extract has shown up as a false positive for benzodiazepines on urine drug tests (Reference 36).

Take some time to consider what resources would be helpful with this situation. Is there a peer support group available to you? Are there nurses you could talk with about your options? Have you contacted your State Nursing Association? You may want to consult with and/or retain a nurse license defense attorney in your State for further assistance. It may cost you a few hundred dollars but it’s worth it to determine how to proceed. Good luck. (see

Never touched it!
Hi, my name Christina and i took a drug test and came back positive for cocaine. I have never touched cocaine. I have been on medication though, Vicodine and clyndamicin … if u know anything of these meds plz help with any advice.


AskDocWeb: Hi Christina. Although some antibiotics have caused false positives cocaine, it is not known if Clindamycin is one of them. The good news is that a GC/MS confirmation test can tell the difference. If your original test was a false positive the confirmation test will come back negative.

Failing a urine screen
My son is currently incarcerated for failing a urine screen. They said that he tested positive for cocaine. He swears he has not used. He is tested on a weekly basis while on probation and when he recently got a bad cold he would not even take NyQuil. He is on judicial release and only had 5 months left to get off probation, it does not make any sense that he would risk it all now. He has 2.5 years in prison hanging over his head.

He went in about 8 weeks ago and they called him a few days later for a random. He then returned the following Monday for his normal weekly screening. The following week when he returned they did the screening and told him he was being arrested for probation violation. He asked why and was told he should know why. After 4 days in jail he request to speak to a public defender and offered to take a blood test. They told him it was too late that it would already be out of his system. Apparently on the first failed screening he tested with a low level and then it progressively increased. He was never notified or questioned until he was arrested. He says he can’t think of anything he has taken or eaten differently other than using a few different topical pain relievers for his toothache, one of which he got from a co-worker.

Could any otc toothache gels/liquids give a false positive for cocaine or could the co-worker have given him a prescribed medication that had something in it that could cause a false positive? We can’t get in touch with the former co-worker and his name has been given to the courts. He has offered to take another urine screening to see if it could possibly be something medical with him since he has been locked up for 5 weeks and if he fails it now, that would indicate the need to do some further testing on their part. He has a lot riding on proving he is not guilty and from day one of the original crime turned himself in prior to speaking with any attorney and told the truth. Unfortunately I don’t know if that will help, but I would think he has some credibility with the Judge.


AskDocWeb: If he did take a prescription medication from a co-worker, that is likely to be a violation of his parole as that is illegal in most places. There is a product used in dental care as a numbing agent called bupivacaine, which may test false positive for cocaine (Reference: 59). It’s sold under the brand names Marcain, Marcaine, Sensorcaine and Vivacaine. Was his urine screen confirmed by GC/MS?

I have been feeling like my legs have lowblood circulation and my kidneys have been hurting so I been drinking cranberry juice eating oranges. I am prescribed diazapam and 60mg vivanse. I have not takeing a vivanse in over 3 weeks. they ran blood test and said liver profile(gen) and methamphetamine abuse (ed). I have not done meth but I do drink twice a week 20 to 25 beers total. I WAS SHOCKED and felt it was a false positive.


AskDocWeb: Hi Mike, welcome to the unintended consequences of the War on Drugs. Neither of your prescription medications would show up as a false positive meth but that could occur for other reasons. Also the beer would not affect the meth test. We believe it is important (for several reasons) to rule out false positive results by following up with additional testing. Getting a GC/MS confirmation test will clarify the present results and avoid problems in the future.

Dirty for THC
I took a asprin and droped the next day, i droped dirty for THC and i do NOT smoke.


AskDocWeb: The Aspirin that is used to treat mild to moderate pain and to reduce fever or inflammation is NOT known to show up on urine screens for drugs of abuse. However, if you think that your test results are false positive then a confirmation test is the only way to go.

Positive for amphetamines
I’ve taken the following medications in the last month: xopenex inhaler, albuterol inhaler, b complex dietary supplement (in large amounts), and ciprofloxacn for a stubborn bladder infection. I tested positive for amphetamines, not meth, just amphetamines. My boyfriend does use methamphetamine, or “ice” and we have had oral sex and unprotected sex and we had unprotected sex, (he ejaculated inside me) right before my UA. I have not touched the the drugs at all, but if I had could that cause a false positive, also when we have intercourse he sweats a lot… Could I be absorbing it into my skin from his sweat?


AskDocWeb: Ciprofloxacn is a common misspelling of ciprofloxacin but it does not show up as amphetamine on urine drug screens. Some of the methamphetamine in your boyfriend metabolizes into amphetamine. In our opinion your exposure to this could cause a positive test result and that would not be a false positive.

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