Feedback on False Positives from Drug Testing, page 99

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: Denied surgery
Date: 8/23/2010
I was recently denied surgery because I was told I showed up positive for cocaine. Since I don’t do cocaine, how is this true? I have reviewed this entire site and saw where amoxicillan can cause a false reading. I take amoxicillan (3000mg) each time before I see my dentist, as I am a liver transplant recepient. Any information you may send me pertaining to this subject would be greatly appreciated. Thank You


AskDocWeb: You ask, “how is this true?” It may not be true because the EMIT urine drug tests are known to have an error rate. That means a percentage of test results are not accurate. In order to find out if you have a false positive result you will have to get a GC/MS confirmation test. If your transplant surgery depends on this then it is certainly worth the effort.

Subj: Cocaine?
Date: 8/24/2010
What are some false positives for cocaine in hair screening?

AskDocWeb: Sorry Toto, the information here applies only to urine drug testing.

Subj: Zofran
Date: 8/24/2010
We have a patient who is taking Zofran, and came up positive on a drug test for syboxone. Do you know of any reason why someone taking Zofran would test positive for syboxone?

AskDocWeb: We were unable to discover any reason for Zofran to cause a false positive on a urine drug screen. Zofran (Ondansetron) is used to prevent nausea and vomiting caused by cancer chemotherapy, radiation therapy and surgery. Zofran is in a class of medications called 5-HT3 receptor antagonists. It works by blocking the action of serotonin, a natural substance that may cause nausea and vomiting.

Subj: positive for Opiates and Oxycodone?
Date: 8/24/2010
Good morning, I recently had a UA done at my Pain Management appt. I currently take Lortab, Morphine Sulfate, Promethazine, Baclofen 4 mg, Vitamin D 50,000 IU, over the counter generic sleep aids, herbal melatonin and a women’s vitamin. My UA showed up positive for Opiates and Oxycodone. The nurse told me that drugs like percocet and oxycotin would cause a positive. I have never taken anything like that! My Mom did give me a Mobic a day or two prior to my test. Why and how would the UA test be false positive for Oxycodone?

AskDocWeb: Lortab is an opioid analgesic and Morphine Sulfate is an opioid agonist. As for the Oxycodone result, we have no explanation for that. There are currently no reports of false positives caused by Mobic (meloxicam).

Subj: False positive for oxycodone?
Date: 8/24/2010
I take Suboxone and I have two false positives for oxycodone. I had one confirmed and it was positive for oxymorphone which I haven’t taken. Can Suboxone cause these to be positive?

AskDocWeb: There are antidotal reports that Suboxone has caused false positives for oxycodone but we have been unable to verify that with a good professional reference. If you find one let us know and it will be added to the list. Please note that in each suspected case of false positive the GC/MS test showed no trace of oxycodone.

Subj: Positive urine for Benzos
Date: 8/25/2010
Hello I am searching and have been for some time now why I keep having a positive urine for Benzo… I am running out of time to prove to the Legal system that I have not taken anything in that family which is valium, zanax, kolonepin. I am on prescription medications and they are aware of this. Is it possible for something else to effect my urine, something I am taking. I was involved in a Drug Court Program for about 16 months and had very frequent urine testing. At least 80% of my test was positive for benzodiazapine but they would have it further tested and showed nothing. I just had a urine drug test and they sent it to the lab and it was positive for benzo. and now they are going to have to have it tested further. Which test would you reccommend? I am giving you a list of my medications that I am currently being prescribed and OTC meds that I took 2-3 days prior to testing, Is it possible that one of these is the reason for my test showing positive?? Any Info. or adv ise Please!!!!! verapamil- hypertension lasix- diuretic methadone- pain and weaning from lortabs phenteramine-weight loss zofran- for nausea excedrin- pain Ibuprophen- pain Albuterol Inhaler-asthma- I have used a lot due to allergy.

AskDocWeb: There have been false positives reported with some of the drugs you list but not for benzodiazepines. When it comes to having additional testing done on a urine sample the GC/MS confirmation test is the gold standard.

Subj: Promethazine
Date: 8/25/2010
Could taking promethazine cause a 60% positive reading for THC? If not what can cause that? My job is on the line.

AskDocWeb: We found three references that say Promethazine has shown up on urine drug tests as a false positive for THC (Ref: 3, 16, 18). Since your job is on the line, sending your sample out for additional testing may be your only hope of saving it.

Subj: Lamotrigine
Date: 8/25/2010
I tested positive for PCP but I have never in my life taken any kind of drugs except Marijuana and that was a long time ago. I am on Lamotrigine for my Epilepsy and I suspect that can be the only reason for the test. Is that possible? Will it show PCP on a GC-MS or a blood test? Thank you very much!


AskDocWeb: (answer revised 6/30/2011) There is a possibility that Lamotrigine (Lamictal) may show up as a false positive for PCP on a rapid urine toxicology screen. The only way PCP will show up in a GC/MS test is if it is actually present in the sample.

Subj: Doxcycline or kidney infections?
Date: 8/25/2010
Can doxcycline cause false positive for opaties and benzo and mifeprex and misoprostol these r abortion pills. Also can tramadol cause false positive for any drugs and if I have kidney infections and lupas make any false positive and the shot humara for lupas and any antibiotics for cocaine

AskDocWeb: Doxcycline is not on our list but 3 sources (References 13, 18, and 20) say that antibiotics have shown up as false positives for heroin and cocaine on the urine EMIT tests. It is not clear if kidney infections or the drugs used to treat them cause problems with drug tests but according to the obstetricians and gynecologists at ( kidney problems may cause a false positive for cocaine.

Subj: Positive for cocaine
Date: 8/26/2010
I did drugs before I was put on probation, cocaine. I stoped. I thought it would be A good idea to take niacim to help detox my body. My po officer said that I have came up positive every time for cocaine, it has been like 4 weeks. I don’t understand. The other meds I take are tylonal with codien, penicillin, mens one a day, as well as naproxen at leat 1000 mg a day. I don’t know what to do I don’t want to go back to jail for something that i am not doing please help.

AskDocWeb: If you check the list, you will see that others have had false positives when using Tylenol with Codeine. We believe that people on probation should be made aware of this list so that they can avoid those things that may cause a false positive. This can be cleared up with additional testing by GC/MS but that test is expensive and often the person being tested must pay for that.

Subj: Oxycontin in vitamin C?
Date: 8/26/2010
Hi AskDocWeb, my child had a cold and was taking a vitamin c powder you mix in your drink from the health food store. She took it to school and was searched and they found the vitamin C and the sheriff tested it and said it was Oxycontin and arrested her. I took the rest of the bag that i bought to them and it tested positive to. but they didn’t arrest me shes been in jail 2 days now. Dose VITAMIN C test positive? and Y? HELP!

AskDocWeb: There is no oxycontin in vitamin C and that vitamin does NOT cause false positives on urine drug tests. However, is it possible that someone may have added oxycontin to the vitamin C?

Subj: Nasal spray?
Date: 8/26/2010
can a nasal spray give a false positive for morphine?

AskDocWeb: Yes, there are reports that 4-Way Nasal Spray has caused false positives for amphetamines and morphine (References 1, 2, and 7).

Subj: Lexapro and ammoxcilin
Date: 8/27/2010
My daughter takes lexapro and ammoxcilin and her drug test showed a positive for opiates. Is this the case with these 2 drugs? Thanks,

AskDocWeb: That seems to be the case with amoxicillin but Lexapro has not been reported to cause any problems on urine drug tests.

Subj: Isn’t there a law?
Date: 8/29/2010
I go to pain management doctor for chronic back conditions. At my last appointment I submitted a urine screen upon dr request. I thought nothing of it because I do not abuse any substances. Two days later I received a dismissal letter from them via mail. When I called to see why, they said they found alcohol in my urine. Only problem is I do not drink I cant even tell you the last time I drank any alcohol; Im talking years. So how is it possible that alcohol showed up in my urine? And what can I do to fight this. Isn’t there a law that even after dismissal from a practice they still have to treat me for 30 days giving me time to find new doctor?

AskDocWeb: Laws vary from one state to the next. For example, in Iowa physical therapy records are NOT considered medical records and can be disposed of without contacting the patient if a therapist goes out of business or moves out of state. To get answers about your local laws, contact your state Attorney General’s office.

Subj: Why is amphetamines considered illegal?
Date: 8/30/2010
I am on probation and my drug test came back positive for amphetamines. I do not use drugs but I have asthma real bad and before my doctor put me on 2 different inhalers I went wild purchasing OTC products, as Vicks Inhalers, Sudefed, primetine mist, a large variety of drugs, just anything I thought help relieve what I thought was a cold I could not get over. I was constanly trying all kinds of nedications before I made myself go to the doctor. I was to embarressed to tell my doctor i tested positived for amphetamines, and to ask if the mixture of all this medication I had been taking would cause a positive reading. Can someone answer this and i dont understand if taking these OTC mediciations can show a false positive why is amphetamines considered illegal? Is amphetamines treated the same as meth and what form does it come in when purchased as meth is. Thank You,

AskDocWeb: Amphetamines are a controlled substance (legally regulated) in most countries because of the risk of addiction and possible drug abuse.

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