Chemistry matters. Join us to get the news you need.

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.


Pharmaceutical Chemicals

Drug Testing And 'Caine' Drugs

November 23, 2009 | APPEARED IN VOLUME 87, ISSUE 47

The "What's That Stuff?" article on dental anesthetics may unfortunately lead some to the erroneous conclusion that cocaine and the so-called caine anesthetics are closely related (C&EN, June 29, page 33). The article claims that with names like benzocaine, some may think that these anesthetics must be derivatives of cocaine.

In turn, the misapprehension is created that commonly used dental anesthetics such as benzocaine may yield false positives in urine drug testing, indicating illicit use of cocaine. A cursory review of the structures for lidocaine, procaine, and articaine shows they lack the ecgonine nucleus. Furthermore, the common dental analgesics are not related to cocaine nor to its metabolites synthetically. In addition, cocaine and its derivatives are Federal Schedule II drugs, whereas procaine, lidocaine, and the other "caine" drugs are unscheduled.

During 16 years as the director of a Florida-licensed and federally certified employment-related drug-testing laboratory that also performed "driving under the influence of alcohol" and "driving under the influence of drugs" work for Florida's 20th judicial circuit, I (Robert White) had ample opportunity to refute many false reasons for a defendant or claimant to explain a confirmed positive "cocaine" urine drug test.

One of the most popular explanations was, "I went to my dentist and he gave me lidocaine. It must be the lidocaine that caused my positive for cocaine." This claim is predicated on the assumption that lidocaine mimics cocaine because both end in caine. It was proven in my lab and others' labs that ingestion of the caine drugs will not precipitate an immunoassay presumptive positive ("screening" result) for the major cocaine metabolite, benzoylecgonine (BE), the primary substance actually targeted by most cocaine immunoassays. In addition, gas chromatography/mass spectrometry (GC/MS) selected-ion monitoring for urine BE does not show any detectable peak for derivatized BE postingestion of drugs such as lidocaine. Similarly, analysis of the same urine for ecgonine methyl ester and parent cocaine by full-spectrum GC/MS reveals no peak for either substance postingestion. Thus, neither parent cocaine nor its metabolites are related to the caine drugs metabolically or immunologically.

In summary, the caine drugs such as lidocaine and procaine have their own structures separate from the ecgonine nucleus of cocaine and its derivatives and their own pharmacodynamic effects. The caine drugs are different both pharmacodynamically and pharmacokinetically, as well as legally, from cocaine. Thus, cocaine and the caine drugs should not be grouped together or confused with one another as that may lead to erroneous medicolegal conclusions that may be inferred from the cited article.

Robert M. White
Peter F. Eisenhart
Naples, Fla.



This article has been sent to the following recipient:

EM (August 9, 2015 9:51 AM)
I greatly respect and appreciate your knowledge and research Mr. White however, there has to be some connection between lidocaine & cocaine because there are several people that this is happening to. I am not a drug user and rarely even drink alcohol but tested positive for cocaine in a hair drug test from my employer. So, to prove them wrong, I went to a different lab and paid for a hair drug test myself and it came up positive again. 3 months prior to the drug test I had been injected with Lidocaine several times for a biopsy. I had also had a tooth pulled and developed 'dry socket' and they gave me petroleum based Xylocaine to keep putting in the dry socket until it began to heal. However, I was told by 3 different doctors that Lidocaine will not show up as cocaine because they are not related in any way. Too many [none drug user's] are losing jobs and reputations because of this. [Something] is obviously being missed. Thank you.
J Gibson (August 11, 2015 9:22 PM)
Trace amounts of cocaine have been detected in everyday items we use from money to cigarettes. Such small amounts won't affect you but could show up in drug screens.
Kams (June 9, 2016 10:18 AM)
I have the exact same problem now .
AMC (August 22, 2016 10:28 PM)
My daughter went to the dentist on the 12th and had 5 extractions. She went to drug court 2 days later and the instant test showed cocaine. They sent it to the lab for confirmation and came back positive again for cocaine. She did not use cocaine and now she is in jail and there is nothing we can do.
Randy Brasfield (August 13, 2015 11:47 AM)
I also lost my job after testing positive for cocaine on a random hair drug test. I had been to the dentist and was given several shots of lidocaine, I haven't done any cocaine so I naturally assumed it to be from the lidocaine. I have paid for drug testing and they keep telling me that its cocaine and I can't get any lab to test for lidocaine and the cocaine to see if it's more than a coincidence. I'd like to clear my name!
Ray Anderson (September 4, 2015 1:49 AM)
I had some major dental work done the past 3 months. Had about eight cavities filled and a couple of teeth needed to be permanently removed. All 5 times the dentist injected me with a couple of shots I supposed n I novaCaine or lidocaine.wasn't sure because I was in a lot pain and I told her I wouldnt be able to tolerate anymore. I was also prescribed lidocaine to use orally to relive pain in my gums and u had a really hard time chewing and still bothers me now due to three teeth I had to permanently removed. I went for a pretty employment drug screening...the results took over a week to come back and the doctor had told me I tested positive for cocaine. I never used cocaine in my life !! There must be some kind of mistake and now I'm without a job.
Daniel (October 28, 2015 6:34 PM)
I believe that in other countries, cocaine is still used for eye and/or dental surgery. So if you took a trip south of the border or some other place for cheaper medical services, you may have been given actual cocaine.
Karry Kaduk (November 2, 2015 9:07 PM)
I had a work related injury on a table saw cutting two finger tips off. After going to two emergency rooms on IV at both with cefazolin sodium, sodium chloride, hydromorphine hci and tetanus/diphtheria toxiods in the first emergency room. And at the second hospital I received enoxaparin sodium, morphine sulfate and ondansectron then at 8:50 pm a urine test sample was taken and sent to workman’s comp. Now all benefits have been denied. So I am livid and very disappointed and then today unemployment denied me benefits also.I can not understand why I am testing positive for cocaine now workmans comp. and unemployment denied and terminated from my job. Hired an atty. but that will take time and financially out of time. can all of these given meds. intraveniously cause this test positive for cocaine
Rene D (November 13, 2015 10:27 PM)
I have never used cocaine but today after having test done in emergeny room was informed that I tested positive for cocaine. I couldn't believe this and upon discharge this Dr. Placed in my records that reason I was there for heart issues and chronic drug abuse. I have used lidocaine topical for arthritis. I have to believe that this is what caused me to test positive for cocaine. Im very upset about this and intend on getting this removed from my records.
Kat (January 13, 2016 12:38 AM)
I was called back to a previous employer and had to take a hair test. The test came back positive for cocaine. Never ever have I touched the stuff in my life. I too had recently had extensive dental work done where on each visit I was given more than one caine drug at one time. I believe the FDA knows that there are trace amounts of cocaine in some of these medications but feel like it's not enough that it has to be reported. I don't know but something is definitely not right. I didn't go looking for this job. I didn't lose a job. The only thing different in my life after this test is them telling me that I use drugs when I know that I never have and that s**t is very frustrating.
Rebecca Jackson (February 15, 2016 2:38 PM)
I also tested positive for cocaineto which I know is false I've use lidocaine patches and some ambesol for my tooth that is it they have made an error in there reading (March 13, 2016 4:24 PM)
I believe that I need a knee operation and I am making anew appointment with my doctor soon to set up with a specialist. My wife has procaine pads from a previous injury and I have been using a few to relieve my knee pain. Will this show up as an illegal drugs on a drug test? (March 21, 2017 5:45 AM)
fionasmith (March 17, 2016 1:43 PM)
I have had several dental appointments and a lot of teeth removed and replaced I have had several injections over a period of a few months, I have recently had a hair strand test to prove I am clean of heroin which came back as expected Negative but I have had positive for cocaine- I don't and wouldn't use cocaine I DON'T UNDERSTAND HOW??/ I AM FIGHTING to get my baby girl 👶 home and this is unbelievable I don't know wat to do am in court tomorrow and am now going to look so bad, please does anyone Know what's going on???????? PLEASE HELP ME!!!!!!!!!! XXX
Betty Penta (May 15, 2016 10:40 AM)
Imy grandson tested positive for hair test and had recently had lidocain at dentist and lidocain patch for back pain How long does it stay in system if they want it repeated wouldn't it be the same
This could cause loosing a job that was a life time dream
Allexsis C. (May 20, 2016 8:27 AM)
So glad I have found this website because I to recently lost my job due to my hair follicle drugtest coming back positive for cocaine and the metabolite present was something called benzolecgonine.I have never done drugs in my life and plus I am also pregnant so I was really in disbelief and didn't know what to do.When I went to the dentist I was given local anesthesia and about 5-6 shots of lidocaine because I was still feeling pain while he was trying to pull the tooth. Now about a week or two after I had my tooth pulled I took the drugtest and about a week later that's when I got a call from my employer saying that they have to let me go because of my positive result for cocaine! I was so hurt and immediately thought that it had to be a mistake because I don't use drugs, after multiple calls of trying to tell them that it had to be some sort of mistake,I was finally called back to do a re-test and it still came back positive for cocaine!I tried to think of everything that could cause something like this to happen and found a few things on the internet also stating that there were some sort of connection with dental work and positive results for cocaine. Really don't know what to do at this point but now I see that it has also happened to you guys as well so I know that it has to be due to the dental work. Something really has to be done about this.! I lost a really good job due to this bs. Smh
mark hall (May 25, 2016 12:48 PM)
my hair strand test came back positive for benzoylecgonine as 0.37 and 0.41ng/mg for 2 sections tested and showed *present- below the Alere cut off rate for cocaine, I don't even use cocaine but have used dentinox for my baby teething and licked fingers after. now my son is being taken off me by social services i'm so shocked
thomas (September 10, 2016 11:10 AM)
Hello, I been drug tested three times at work, for head hair twice, three months apart and then a random test three months later from my armpit hair, I test positive for cocaine, I have not touch the stuff in over 25 years, I had a lot of the caine medicines in me from hip injections, teeth pulled, and a cyst removed twice, six shots in me and a lot of lidocaine, and other caine medications, but drug labs ruled these out stating that the gcms confirmation test found the metabolite benzoylecgonine, I didn't have large amounts but over the confirmation level. surely, these caine medicines have to be causing all these positives, look at how many people are disputing this, and if not, what else or other drug if taken with these lidocaines can create this metabolite, im pretty upset about this, haven't slep, lost weight worrying about it, increased my smoking, and had anxiety attacks, this is not right, something is wrong in the testing field, not to mention the antibiotics and steroid injections in me, can anyone help me,
Rene Labonne (October 30, 2016 9:02 AM)
Hi all , i lost my job 2 month ago because i tested false positive for cocaine . I work on pipelines construction , been doing that kind of work for 37 years and this has never happend to me . Am 57 yrs old male . I dont even drink . I asked to be " re-test" and my request was denied . Not even my union wanted to help me . In fact , they required me to attend a drug counselling session ! I live in Canada , i tried to find a lawyers , but of course they want tons of $$$ . Now i cant sleep , lost weight , depression , etc . Dont know what to do next . But for sure i want to clear my name and reputation . Thanks for reading me .
Enel Nerestant II (November 9, 2016 3:37 PM)
I have encountered the same misfortune. I'm on probation and went to a drug class and afterwards gave a u.a and was told the very next day I had tested positive for Cocaine!!! I have been confined to my home due to needing either a hip replacement or another orthoscopic surgery and therefore I've been given a couple of injections of lidocaine.This is very disturbing to think you could possibly end up incarcerated and taken away from your family for a flawed drug screen. Not to mention those who administer the drug screens aren't lenient nor do they ask you to just bring proper documents to show what medical conditions you are dealing with or any kind of medical treatment you've received be it hospital or primary doctors office. This saddens me to see that so many have endured or suffered such misfortune which might I add is a great miscarriage of justice of the law.
B Vieira (November 9, 2016 6:15 AM)
I to have just recently taken a drug test which had yielded positive results for cocaine. I really never used cocaine in my life,ever. I have been using this New ky duration lidocaine 9.6% spray and that's the only thing I can think of that could've caused my false positive drug test for cocaine. I'm truly shocked and upset because my freedom is now at risk,because I used something I bought off the shelf at Wal-Mart. Any answers? please feel free to comment. Plz
J Rivet (December 8, 2016 7:30 PM)
Hello. I have not had an issue with a test concerning Cocaine, though considering what I found in ask me research I may have that issue soon. False positives are usually found in the cases of liver and/or kidney disease, topical ointments derived from cocaine, and Amoxicillin.

I was on Amoxicillin for about a month due to an abscessed tooth, so if anyone else had to take it for their Dental work, or injuries, this may be why you came back positive. Also, check your liver and kidney health. I hope this helps anyone.
Irvin Harris (February 9, 2017 1:11 PM)
Hello everyone I was on a regiment of 875 milligrams of amoxicillin for an infected tooth no I heard all the comments about lidocaine and epinephrine and stuff like that what I came up positive for a drug test cocaine in my urine so what I did was I went and had a hair follicle test done and a medical laboratory and the results came back negative for everything I'm not saying that the lidocaine or epinephrine did it but I definitely had to be the 875 milligrams all of amoxicillin I too lost my job because of it I am 55 years old and have never done drugs
Angela (February 21, 2017 10:26 PM)
I had a hair follicle drug test done for pre employment. In the last three months I've had a root canal, two fillings and 6 crowns done. I tested positive for cocaine! I have never done illegal drugs. I had my dentist send every medication that he used during my procedures and a list of the antibiotics and pain pills that he gave me. The lab said that there was no link to those drugs and cocaine. I can't believe this because I have never used cocaine before and I just don't know what to do! After reading these comments, somethings need to change!
James (March 13, 2017 8:45 PM)
My wife is now in jail for her test coming back positive for cocaine. Dentist has her on Amoxicillin, P.O.repeatedly accused her of using it, which she doesn't at all. She was in tears made worse by the gotta lock you up.
winona lee (March 21, 2017 7:46 AM)
The medical system is so messed up. Its a science and therefore always being changed on what we beleive is fact. The worst part is the narrow minded judges and PO s that dont even look past the failed test. Im praying that a good lawyer will make a ton of money when they take on these bogus hair folical testing companys.And cause all to be educated on false positives in the urine and hair test. This is crazy that so many people have suffered at the hands of this science
Dianne (April 12, 2017 6:50 AM)
I have been going to a pain clinic for my meds for my disability and the pain that I suffer from and when asked for a UA didn't have a problem at all giving one. until the doctor came back and said my UA was dirty with heroin and cocaine. Now I no longer have a pain clinic to go to and a false reading in my medical records. I am blown away of the count of all these people who have lost jobs and even their children due to these false reading they get from their doctors, clinics ect. There has got to be something that we can do to clear our names in this mess. But until that is done I either suffer through the pain that is so bad to the point of my getting sick to going to the streets and looking for the same drug that caused me all the drama BS that I have endured...... lost and in pain.
Debbie (May 13, 2017 11:44 PM)
I have Sjogrens disease and because of that my teeth have went bad and I had to postpone my dental surgery. I have several inflammatory auto immune diseases so I have recieved several Perscription strength Lidocaine ointments and creams, I have been with my Pain Doctor for years and last month I used a lot of the lidocaine ointment orally to numb the pain from my teeth I did not think it would test as a different metabolite on my urine test so I did not mention it Needless to say the Pain Doctors Nurse called me to tell me Doc won't see me no more I was devastated I cried so hard because I never did hard drugs or abused my pain meds now they are sending me ways to. Come off my pain meds, My Gosh I won't walk again my body will be so painfull I will lay in bed and not want to be touched.

Leave A Comment

*Required to comment