Feedback on False Positives from Drug Testing, page 69

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: Zoloft and methocarbomal
Date: 7/29/2009
I have not taken valium in over five weeks but I continue to test positve intox screen. I also take zoloft and methocarbomal. Could that effect the tox screen?


AskDocWeb: It might be the Zoloft which has been reported to sometimes show as a false positive for benzodiazepines (Reference 31).

Subj: Viagra false positive
Date: 7/30/2009
Can Viagra cause a false positive for cocaine in a hair screen?


AskDocWeb: There are no reports of Viagra showing up as any kind of false positive on drug tests.

Subj: Zantac (ranitidine)
Date: 7/30/2009
I took a drug test today and it come out positive for methamphetamine, and this happened to me 3 weeks ago, which came back negative after they sent it to lab. Both times I have taken Zantac (ranitidine). Could that be why it comes out positive on a stick? please email me and let me know. Thanks,


AskDocWeb: Responses are posted so that others can also benefit from your question and answer. Yes, the stick test is not perfect and a certain percentage of the results are false positives. That is why they send it to a lab for a GC/MS (Gas Chromatography/Mass Spectrometry) confirmation test and false positives come back negative.

Subj: Naproxen
Date: 7/30/2009
I would like to know if Naproxen can give me a false positive in a drug test…if is true what drug?


AskDocWeb: Naproxen (Aleve) may show up as a false positive for marijuana (THC) according to references 1, 3, 16, and 21.

Subj: Positive hit for Amphetamines
Date: 7/31/2009
My sister, a nurse was suspended for an initial positive hit for Amphetamines. She is taking Gabapentin, Effexor, ranitidine and a stool softener as well as red yeast, Vitamin E, omega 3 fish oil and calcium + d. Would any combination of these trigger a false positive. She’s furiously waiting reinstatement while a comprehensive test is performed. Thank you for any insight you may offer.


AskDocWeb: Ranitidine has been reported to sometimes show up as a false positive for Amphetamines on urine drug tests (Reference 32).

Subj: Atenolol?
Date: 8/3/2009
I’ve been clean for 52 days of THC I’m still testing positive urine test. I also am taking Atenolol for high blood pressure can this cause a false positive for THC?


AskDocWeb: Atenolol has not been reported to show up as any false positive on urine drug tests.

Subj: Documentation for false positive
Date: 8/4/2009
I was just told I tested positive for cocaine in my urine. I have been completely drug free for two years, very, very proud of that. I never even used cocaine when I had a problem. Not the drug of my choice at that time. My problem is, I did take Amoxicillan during the testing period for an infection. I was told this could produce a falst positive for cocaine. If I cannot provide some evidence that this is documented in some medical literature or some physician can confirm that this is a possibility, I face FIFTY years in prison tomorrow for something I did NOT do. Finally got my life together, after selling 5 pills to a “friend” for the first time ever at the age of 21. My suspended sentence was 50 years for this first offense. I’ve cleaned up my life completely now and am devastated and terrified as the value of my freedom has more meaning to me than ever after my mistake 2 years ago. Can you tell me about the incidence of false positives with Amoxicillan and where else I can find validation information on this? My life actually is hanging in the balance…


AskDocWeb: For references about Amoxicillin showing up as a false positive for cocaine see numbers 13, 16, 18, 20, 21, 26, and 29 on the Reference List.

Subj: Diphenydramine?
Date: 8/5/2009
Does diphenydramine show up on urine drug screen test?


AskDocWeb: The closest listing we have to diphenydramine is diphenhydramine which has shown up in drug screen tests. See references 24 and 32.

Subj: Buspirone or Carbamazepin?
Date: 8/6/2009
Can Buspirone or Carbamazepin test positive for cocaine?


AskDocWeb: Neither one is on the list.

Subj: False positive for cocaine?
Date: 8/7/2009
HI I’m not quite sure what a false positive for cocaine would be from because I don’t due drugs, I do drink alot of different teas to help my immune system and tonic water 2-3 times a day for a bum knee and I’m wondering if these items would give me a false possitive for cocaine I have never ever taken? Thank You.


AskDocWeb: It may be the tonic water, which has shown up as a false positive for cocaine. (According to references 16 and 18)

Subj: Pantoprazole – Protonix
Date: 8/10/2009
I have had two low dose THC test and do not smoke pot but do take pantoprazole or better known as Protonix, some days one and some days two. Will this cause a false positive?


AskDocWeb: Yes, pantoprazole has been reported to sometimes show up as a false positive for THC (Reference 37, page 4).

Subj: Positive for cocaine and PCP
Date: 8/10/2009
I took a drug test today that showed positive for cocaine and PCP. I have not used cocaine in more than 20 years and have never used PCP. I take lamictal for epilipsy. Could this be? I don’t know about the types of tests but I do know that it was urine and the test reads on the cup.


AskDocWeb: (answer revised 6/30/2011) A hospital in Florida has reported that lamotrigine (Lamictal®) has shown up as a false positive for Phencyclidine (PCP) on rapid urine toxicology screens.

Subj: Tested positive for benzos
Date: 8/12/2009
I attend the McLeod Center in Boone, NC. On July 28,09 I tested positive for benzos then exactly 1 week later on August 4,09 I tested negative then 3 days later on August 7,09 I tested positive on a stick test in which was dropped from L-5 to L-1 and the same urine used on the stick was sent to a lab for testing and it came back negative. What is doing this to me because the only thing that I have taken is Alka-Seltzer PM, Cough Med w/antihistamine in it, Ibuprofen 800(headaches) on a daily basis, Pepcid(heartburn) on a daily basis, and Lasix(water retention) on a daily basis. Could any of these have done this to me? Thank You.


AskDocWeb: Several of those have caused false positives but not for benzos. However, you may want to check the ingredients in your cough med against this list.

Subj: Arrested for a smudge bundle
Date: 8/12/2009
I was first detained by an officer when returning to my car from a bird watching hike. My smudge bundle (herbal incense) was confiscated from me and subjected to a field test. It tested positive for cannabis. What was in it was sage, sweetgrass, lavendar and copal. I had previously purchased it in an Airport Gift Shop and carried it on the airplane in my bag, right through security! I do not even smoke marijuana and offered to be tested. I managed to throw enough doubt on the officer that he released me, saying that if it tested positive in the crime lab they would come and arrest me. I was arrested 90 days later and charged with Felony possession of Cannabis (over 20 grams in Florida). I spent a night in the Women’s Prison. Turns out the Crime lab had never tested my smudge bundle, but the officer had arrested me anyway. After this was revealed, my attorney had them test it and of course, it was clean. Charges were dismissed. I had done some research online and received help from John Kelly, forensics expert who is writing a book, “HOW TO OBTAIN A PRETRIAL DISMISSAL OF MARIJUANA CHARGES OR AN ACQUITTAL OR AN EXONERATION.” I highly recommend his help if you run into this kind of trouble!


Subj: Positive for dioazipines
Date: 8/13/2009
My doctor has me on prozac – hydroxize – clonodine – amitriptilyne and when I went in to take a urine test they said it came pack posative for dioazipines. Over the counter I have taken excerin migraine, benedryl, and sometimes a sleep aid. – none of these on a regular basis so I was wondering if you help me figure out why I’m testing for something I not taking?


AskDocWeb: Hopefully you can find your answer on this list of things that have shown up as false positives.

Subj: DTS Screening Services
Date: 8/14/2009
Teference address (on the references page) doesn’t work: 33. DTS Screening Services: great site – thanks!


AskDocWeb: Thanks for letting us know. Before removing this resource we will give them some time to find out if this is temporary or not.

Subj: Coricidin cough and cold
Date: 8/15/2009
My good friend is in the Navy. He was given a urine test and when the results came back he tested positive for dextroamphetamine. He is my room mate and I know for a fact that he dint use that stuff. The weekend before the test he had been using coricidin cough and cold we think that caused the misunderstanding. He is getting kicked out and I need to know if this is possible to help defend him thanks


AskDocWeb: Sorry Clint, that cough medicine is not on the list. You might check the ingredients to find out if one of them might be causing the positive result.

Subj: Inconclusive results
Date: 8/15/2009
I recently took a pre-employment drug screen and the results came back inconclusive. They told me to list everything I’ve taken in the past two weeks. I had taken Tylenol, IB Profin, Tums, and Maalox, I am also takin an anti-depressant prescribed to me called paroxetine ER 25 mg tablets once per day. I was wondering what this means and if any of the drugs listed could cause “false-positives” or I suppose why it could be my test came back inconclusive?


AskDocWeb: Inconclusive results means that there was something showing up on the test but they couldn’t be sure of the results. Both Ibuprofen and Tylenol are on this list.

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