Summary: As well, false positive urine tests for cannabinoids have been reported among those taking Sustiva. doi: 10.1002/emp2.12702. When a patients urine drug screen tests positive for methamphetamine by mass spectrometry, the result has serious implications for the patient and the provider. Labetalol can also cause a false positive for amphetamine or methamphetamine because a labetalol metabolite is structurally similar to amphetamine. could cause a false positive result for PCP or methadone. Dr. Brian Staiger is a licensed pharmacist in New York State and the founder of the Q+A website PharmacistAnswers.com. Additionally, GC-MS quantifies the amount of drug present in a sample. Poppy seeds. Common Vitamins Supplements can cause a false positive test. A comparison of the chemical structures of . Some other medications that can cause a false-positive result can be ADHD meds such as Ritalin (methylphenidate), Quinolone antibiotics like Levofloxacin or Ofloxacin, or Metformin . Medications that have been reported to cause false-positive results for methamphetamine or amphetamine include: The easiest way to lookup drug information, identify pills, check interactions and set up your own personal medication records. Drug-free workplace guidelines and resources. What Does M AMP Stand For On A Drug Test? Prescription use of propoxyphene may cause a positive test result because the cut-off concentration for propoxyphene in urine (300 ng/mL) can be reached after medical use of this drug. He's answered thousands of medication and pharmacy-related questions and he's ready to answer yours! Tim Thoelecke, CSAPA, is the founder of InOut Labs. Subscribe to Drugs.com newsletters for the latest medication news, new drug approvals, alerts and updates. The FDA states that "certain foods, food supplements, beverages, or medicines can affect the results" of some drug tests. Cutoff values were developed to mitigate false-positive results, especially in the workplace. Among its few physiological effects is vasoconstriction, which makes it useful for nasal decongestion.. We comply with the HONcode standard for trustworthy health information. 4,004. Centers for Disease Control and Prevention (CDC). Confirmatory tests are much more specific, but are costly, take more time, and require experienced laboratory personnel. Five common medications can cause a false positive for methamphetamine. that you have taken it., Riboflavin, also known as B2, is found in hemp seed oil and may return a. is the non-psychoactive portion of the marijuana plant that has become a very popular remedy for everything from pain control, to promoting sleep, to helping relieve anxiety. Promethazine is part of a group of medications called phenothiazines. Rifampin, an antibiotic used to treat tuberculosis, can also lead to a false positive. Yes, Adderall can and will show up on a basic methamphetamine test. If it is prescribed, make sure you have the label from the pharmacy, which will show that the medication was prescribed to you. The use of Dexedrine (Dextroamphetamine), Ritalin (Methylphenidate) and Adderall (made of four different amphetamine compounds) should be put on hold if . The immunoassays can cross-react with commonly used medications or its metabolites and show a false positive level for substances that are banned by an employer. Can OTC and prescription drugs affect a pregnancy test? The most commonly used tests to screen urine for drugs of abuse are immunoassays, even though false-positive results for drugs of abuse have been reported with a number of these rapid-screening products. Ibuprofen is still frequently reported in resources as a possible cause for false-positive cannabinoid immunoassays. Yes: how long depend on the dose, and how long you have been taking it. PMC They have been shown to trigger a false positive urine result for opiates. What drugs are likely to interfere with urine drug screens? D-methamphetamine increases alertness, concentration, energy, and in high doses, can induce euphoria, enhance self-esteem, and increase libido. These traits make d-methamphetamine very attractive to a potential abuser. Prescription methamphetamine (Desoxyn) is composed entirely of the d isomer. After a California mom's post about testing positive for meth due to an inhaler went viral, the questions of whether an inhaler could cause a false positive on . The effect lasts longer than with cocaine, it is cheaper, and it is easy to make with commonly available ingredients. False-positive results Due to the potential for cross-reactivity associated with immunoassay urine drug screens, several prescription and non-prescription drugs have been reported to cause false-positive results. A false positive is when a drug test shows the presence of a medication or substance that you didn't actually take. With CBD available in everything from drink powders, to weight loss formulations, to tinctures of all types, false positive urine screenings for THC will become more and more common, warns Dr. McFadden. This Is The Industries Dirty Little Secret. Furthermore, if they can prove they are taking a medicine that can produce a false positive (by producing a legitimate prescription), the administrator may schedule another test 30 to 60 days later. In rare cases, a false positive might occur, but it will be most likely within several hours of exposure. Additional factors such as drug interactions, dose and frequency intervals, chronic versus occasional use, and time of last ingestion can all affect the detection window. Certain antidepressant drugs are more prone to false-positive readings. Doxylamine (the active ingredient in Unisom) can also trigger a positive drug result for methadone, opiates, and PCP. Disclaimer. Although the affinity of the antibody for these substances is much lower than for fentanyl, if they are present at sufficiently high concentrations, they can cause a false positive result [24, 25]. What Medications Can Cause A False Positive For Methamphetamemes Online Shop Are Blood Pressure Meds Fast Acting Rubbing Neck To Lower Blood Pressure Horse Chestnut And Blood Pressure Meds What Helps High Blood Pressure Go Down What Medications Can Cause A False Positive For Methamphetamemes.. And counting the time, it has been blood pressure meds and chronic cough nearly a day since what . Accessibility People taking the HIV medication Sustiva (efavirenz) may obtain false positive drug test results. Gas chromatography/mass spectrometry (GC-MS) is the gold standard for confirmatory testing. They have been shown to. Researchers are studying how the body handles chemicals that may test . 2,6 In addition to medications, several other substances have been associated with false-positives, such as baby wash products, supplements, and food. According to the Drug Abuse Warning Network, 6.6% of emergency department visits involving illicit drugs in 2009 were due to methamphetamine.. Pseudoephedrine, the decongestant found in original Sudafed (the kind you have to sign for) can/will cause a false positive under one of those two test columns. https://www.practicalpainmanagement.com/treatments/pharmacological/non-opioids/methamphetamine-urine-toxicology-depth-review, Did A Vicks Inhaler Cause My Positive Test? Analytes. Rifampin, an antibiotic used to treat tuberculosis, can also lead to a false positive result for opiates. MeSH Used as an antidepressant, for weight loss, and smoking . The trazodone metabolite meta-chlorophenylpiperazine can cause false-positive urine amphetamine immunoassay results . She took the medicine twice a day (at 8 am and 8 pm), and the last dose was administered 9 hours before ED access. New DOT Drug Testing Cutoff Levels 2021/2022. Thats because common. In time, it became clear that methamphetamine was dangerously addictive. Frequency of false positive amphetamine screens due to bupropion using the Syva EMIT II immunoassay. What Can Cause A False Positive For Methamphetamines, List Of Worst Foods and Drinks For Brain Health, The Benefits of Mindfulness: Sherief Abu-Moustafa Shares How To Incorporate it Into Your Life, How to Get a Medical Marijuana Card in California, How Your Blood Group Increases Your Risk Of Developing Some Diseases, WHO sends health supplies to reach 400 000 people impacted by the earthquakes in Trkiye and the Syrian Arab Republic, Longstanding WHO partners to enter into official relations with the Organization, WHO launches new roadmap on breast cancer, Celebrating World NTD day with a photo exhibit: Reframing Neglect. Less commonly, antidepressants have been known to trigger false . However, these antibodies may detect drug metabolites with similar structure and characteristics to methamphetamine, leading to false-positive results. False positive results on urine drug tests can happen. 13. During World War 2, methamphetamine similar in structure to amphetamine was usedto keep military personnel alert and to improve endurance and mood. Bupropion and desipramine--two antidepressants that many people take for depression--may cause a false positive for amphetamines in routine urine drug screening. The first test is an immunoassay (IA) screening test for the amphetamine class of medications, which includes both amphetamines and methamphetamines. However, certain infertility medications containing hCG may cause a false-positive result. Dextromethorphan, the active ingredient in. In very rare cases, you can have a false-positive result. Accessed April 8, 2021. Purpose: may obtain false positive drug test results. Results from such tests should be confirmed using additional analytical methods, including gas chromatography-mass spectrometry. False-positive drug screens are commonly documented in case reports. Benzodiazepine use may result in low concentration levels that are not detected on screening, which is common for clonazepam. Promethazine. In addition, benzphetamine (Didrex) is a schedule III medication approved for treatment of obesity. This might look like someone used illegal drugs (such as methamphetamines or opiates) when they did not. It is used for its powerful euphoric effects, which are similar to those of cocaine. Common medications like Trandate (labetalol), a beta blocker used to treat hypertension, and Cardizem (diltiazem), a calcium channel blocker used to treat hypertension and chest pain, may result in false positive drug test results for LSD. Didrex is metabolized to methamphetamine. J Anal Toxicol. Urine tests can detect more recent drug use, while hair follicle . The main issue is the tests themselves. "Adderall, which is a methamphetamine base. Often times, drugs that are NOT being tested for can react with the wrong antibody (i.e. Methamphetamine is illegal except when it is prescribed by a physician for a very limited number of medical conditions. These prescriptionsand other substancescan skew the results of a screen for illicit substances, Find out if caffeine interacts with these prescriptions for hypertension and heart problems. My recommendation to anyone taking these medicines who might be drug tested is first and foremost to be honest with the tester, says Dr. McFadden. A 2008 study by the Mayo Clinic found multiple substances that could . The temperature of urine should be between 90 to 100 degrees Fahrenheit measured within 4 minutes of collection; the pH should be consistent with the range of 4.5 to 8; the specific gravity should be between 1.002 and 1.030; and the creatinine should be greater than 20 mg/dL. The MS confirmation test can come back with 4 possible results: 1) no amphetamines detected; 2) amphetamine only detected; 3) methamphetamine only detected; and 4) both amphetamine and methamphetamine detected (Figure 1). Mandatory guidelines for federal workplace drug testing programs. Cureus. In addition a number of other medications and their metabolites can also cause false positive result for Methamphetamines they include; Metformin: Metformin (Glucophage) is the most commonly prescribed oral medication for diabetes. Metformin. Urine is most commonly used due to its ease of collection. Aug 2, 2010 . Infants tend to have more dilute urine, which reaches adult osmolarity around the age of 2 years. Positive results on urine immunoassay screening should be considered presumptive, and confirmatory testing with GC-MS should be considered to confirm the findings. 2015 Dec;136(6):e1625-8. DMAA (1,3-dimethylamylamine), found in some dietary and weight-loss supplements. Purpose. As we consider the 4th wave of the pandemic, it can be expected that drug users will need to test stimulants to see if they contain fentanyl. in the United States, but if you consumed the tea in another country like Bolivia or Peru, you receive a positive test result for cocaine. A false-positive test result means that your drug test shows the presence of a medication or substance that you aren't actually taking. HHS Publication No. 2012;12(10). Amitriptyline might trigger a false positive on a urine test that is testing for the hallucinogenic drug LSD (lysergic acid diethylamide). Pharmacy names, logos, brands, and other trademarks are the property of their respective owners. Several common prescriptions, over-the-counter medications, herbs, vitamins, and even some foods could trigger a false positive drug test. , and are well known to cause a false positive for amphetamines and methamphetamines. Research conducted at Boston Medical Center shows that drug tests produce false positives in 5% to 10% of cases. , its highly unlikely that secondhand smoke will cause a false positive test for marijuana. No cross-reactivity was found for other . Roopa Sethi, MD; Amad Din, MD, MPH; Ryan McAllister, MD; and Andrew Lester, MD. One is a stimulant, the other is sedating. Safdari KM, Converse C, Dong F, MacDougall NA, Hyer K, Runyon A, Ahlering H, Comunale ME. As medical and recreational use expands across the country, heres what your patients need to know about potential interactions, Its best to steer clear of these things while taking this blood pressure medication, Research conducted at Boston Medical Center shows that drug tests produce false positives in 5% to 10% of cases. Thats because the chemical structure of phentermine is similar to that of an amphetamine, so if youre taking the drug, it is likely to appear as a positive result on a 5-panel urinalysis. Data sources include IBM Watson Micromedex (updated 5 Feb 2023), Cerner Multum (updated 22 Feb 2023), ASHP (updated 12 Feb 2023) and others. My question Im in pain mgmt and I take norco as needed everyday. Additionally, you can ask to take a more accurate and conclusive test that can detect drug compounds in a specific manner such as gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). The drug has been linked to false-positive drug test results for amphetamine. Accessed October 9, 2012. Hair: Trazodone metabolites may be stored in the hair shafts and show up for a maximum of 90 days, similar to other illegal drugs. Ferguson M, Borowiak E. Ask the Expert: False Positive Amphetamine Urine Screens. These tests are only 95% accurate. International Agency for Research on Cancer - Screening Group. Accessed April 8, 2021. With CBD available in everything from drink powders, to weight loss formulations, to tinctures of all types, false positive urine screenings for THC will become more and more common, warns Dr. McFadden. What exactly is Captagon and why was it banned? InOut Labs is a nationwide provider of employee drug testing services, and your best choice for affordable, direct-to-consumer health tests. Answer. yes it will show as a false positive in the drug screen urine test. I would appreciate it if you please leave a five star rating at the top left part of your screen, since this is the only way I have tank credit for this answer. Drug detection times Ranitidine has been known to cause false positives for amphetamine on drug . October 18, 2018. (2019). Let outsiders enter, so our understanding of the strength of what medications can cause a false positive for methamphetamemes their students is very superficial. methamphetamine. This is because many prescription drugs contain amphetamines, or can trigger false positive AMP results. (SMA) 11-4659, DAWN Series D-35. Taking Sudafed can result in a false positive for amphetamine or methamphetamine. If the IA test is positive, the sample is analyzed by MS to determine whether it was an amphetamine that caused the reaction. Laboratory principles. With a valid prescription, an appointed Medical Review Officer (MRO) can rule out false positives. As noted, the first test is the IA screening test. Conclusion: Abuse and misuse of prescription and illicit drugs is a growing concern, with 11.7% of the U.S. population over 12 years of age reporting illicit drug use in 2018, an increase from 7.9% in 2004.1,2 Drug testing is frequently used in clinical setings to identify substance-use disorders, confirm medication adherence, or identify overdoses. A false positive can potentially lead to a loss of employment, jail time, loss of privileges under probation, revocation of medical license, and exclusion from competitive sports. Prednisone As well, false positive urine tests for. The table below is just a sampling: Drug-Testing Target. Hair drug test: Positive doesn't always mean positive. If only amphetamine is detected, once again no further testing is needed. eCollection 2022. The active ingredient in Zantac, ranitidine is an H2 blocker, most commonly used for acid reflux. The most commonly used tests to screen urine for drugs of abuse are immunoassays, even though false-positive results for drugs of abuse have been reported with a number of these rapid-screening products. I would counsel [anyone who received a false-positive test to ask] the administrator to do a more specific test, says Dr. McFadden, who recommends samples be sent away to labs to have a more specific mass spectroscopy assay done. National Library of Medicine It can feel a little unnerving to be asked to take a drug test, and it is important to know that there are some medications and other substances that could cause a false positive drug test result. Prescription drugs which cause false positive amphetamine tests include: Ritalin. 2015;15(1). 2014 Sep;38(7):387-96. doi: 10.1093/jat/bku075. 1-3 It was prescribed to the patient for symptomatic treatment of irritable bowel syndrome. Know if the meds you are taking might cause a false positive and notify the administrator of the test. Learn how we can help. They both use similar principles. Cold remedies, hay fever remedies, nasal decongestants, diet pills, fluoxetine (Prozac), methylphenidate (Ritalin), bupropion (Wellbutrin), beta blockers (blood-pressure remedies) Barbiturates. Patient variability in body mass, urine pH and concentration, and renal and hepatic function can also affect the detection window. Coca tea is made from coca leaves, which are part of the coca plant from which cocaine is derived. The pain medication, . A drug metabolite is a remnant of the drug after being broken down by the body, and the most common metabolizer of a medication is the liver. Mexiletine and False Positive Urine Drug Screen for Amphetamine: A Case Review. Epub 2015 Dec 13. This means you're not pregnant but the test says you are. Hair drug testing can be used to determine drug abuse over a prolonged period of time, and also allows solicitors to establish a client's pattern of change. Then there's . When a specified drug is present in a test urine sample, an antibody binds to it and produces a reaction. Ofloxacin has also been shown to cause a false positive test for amphetamine or methamphetamine. Substance Abuse and Mental Health Services Administration (SAMHSA). 'cross react'), resulting in a 'false positive'. False-positive interferences of common urine drug screen immunoassays: a review. Avoid smoking, alcoholic beverages, and unnecessary medications. https://www.uspharmacist.com/article/urine-drug-screening-minimizing-false-positives-and-false-negatives-to-optimize-patient-care#:~:text=The%20FGAs%20chlorpromazine%2C%20prochlorperazine%2C%20haloperidol,cause%20false%2Dpositive%20LSD%20results.&text=Thioridazine%20may%20additionally%20cause%20false,in%20structure)%20and%20methadone%20results. The d,l-isomer test also is performed by MS. Understanding each of the 3 testing steps is essential to clinical decision making related to patient care. Both d and l forms test positive by both immunoassay and most confirmation assays. DISCLAIMER: The topics and articles published on this website including text, graphics, videos info graph and other material are for informational purposes only and should not be substituted for professional medical advice. It can also be used as an adjunct treatment for allergies. All of the following medications have documented cases of causing a false positive for either amphetamine or methamphetamine: Amantadine. By identifying medications that contribute to false-negatives and false-positives . , and other over-the-counter cough suppressants, may cause a drug screen to be positive for opiates and/or PCP. Moeller KE, Kissack JC, Atayee RS, Lee KC. Saitman A, Park HD, Fitzgerald RL. The potential for false-positive UDS results was identified for the following medication classes on the clinic formulary: antihistamines, antidepressants, antibiotics, analgesics, antipsychotics . Similarly, Zoloft (sertraline) may show up as a benzodiazepine. Some examples include NSAIDs, dextromethorphan, and some antidepressants. Epub 2014 Jul 1. Clinical Interpretation of Urine Drug Tests: What Clinicians Need to Know About Urine Drug Screens. drbrush, Board Certified Physician. With increased dose or prolonged abuse (either binge or chronic), an individual may experience a set of secondary effects that may include increased anxiety, irritability, aggressiveness, paranoia . Once methamphetamine is confirmed positive by MS, a third test may be performed to ascertain the ratio between the 2 isomers of methamphetamine. Labetalol: Labetalol (Trandate) is both an alpha- and beta-blocker drug used for blood pressure control. A number of routinely prescribed medications have been associated with triggering false-positive UDS results, and the most commonly used tests to screen urine for drugs of abuse are immunoassays, even though false- positive results for drugsof abuse have been reported with a number of these rapid-screening products. So, if you are like most people who dont take the time to study the fine print, here is a list of prescriptions and over-the-counter medications that could cause a false positive drug test. The implications of potential false-positive urine drug screen (UDS) results for patients receiving commonly prescribed medications were evaluated. Drugs.com provides accurate and independent information on more than 24,000 prescription drugs, over-the-counter medicines and natural products. Clinical interpretation of urine drug tests: what clinicians need to know about urine drug screens. Methods for urine drug testing Please enable it to take advantage of the complete set of features! Methamphetamine increases synaptic dopamine, primarily by stimulating presynaptic release rather than by blocking reuptake. Bupropion (generic Wellbutrin). Adderal Also causes a false positive methamphetamine test. Wygesic. Nelson ZJ, Stellpflug SJ, Engebretsen KM. Amphetamine positive urine toxicology screen secondary to atomoxetine. Ranitidine. This might look like someone used illegal drugs (such as methamphetamines or opiates) when they did not. Epub 2015 Nov 2. Heres what you should know if youre prescribed this antibiotic. Pseudoephedrine. Based on a 1991 Department of Health and Human Services Technical Advisory, a d-methamphetamine level that is >20% of the total is considered indicative of a source other than an OTC product or a metabolite of selegiline. These sources could include a prescription medication or illegally manufactured methamphetamine. These tests do not use antibodies and can accurately determine the exact molecule being looked for. Mayo Clin Proc. It is also a good idea to avoid taking any vitamins or similar supplements until you take the test. Alcohol in hand sanitizer (from heavy use), certain liquid medications, and mouthwash or other breath cleaning products could cause you to test positive for drinking alcohol. October 12, 2022 by World Wide FAQS. The DHHS cutoff values were developed for adults, and lower thresholds should be used for infants. What medications can cause a false positive for methamphetamines? False-positive results can be due to a laboratory error, but the most common reason for a false-positive methamphetamine test is other medications or substances that have a similar structure to methamphetamine. The l form is available over-the-counter as the active ingredient of a specific Vicks inhaler and is a metabolite of certain prescription medications. Quetiapine, which treats schizophrenia and bipolar disorder, can wrongly show that you have methadone in . Additionally, many enzyme immunoassays are designed to detect nordiazepam or oxazepam, metabolites of diazepam, chlordiazepoxide, and clorazepate.11 Therefore, lorazepam and clonazepam are not reliably detected by immunoassay, and GC-MS should be utilized if detection of these agents is desired. There are chances that they show up as false positives for AMP during the test. What Can Cause A False Positive For Methamphetamemes . Quinolone antibiotics: Quinolone antibiotics such as levofloxacin (Levid 500), ofloxacin and ciprofloxacin are commonly prescribed for urinary tract infections, pneumonia, and sinus infections among other things. 2011 Jun;7(2):105-8. doi: 10.1007/s13181-010-0131-5. Prednisone is a corticosteroid that is detectable in your urine, so if you are taking the drug, it is possible that you will test positive for steroids. Immunoassay technology uses antibodies to detect drug metabolites. Labetalol: Labetalol (Trandate) is both an alpha- and beta-blocker drug used for blood pressure control. Most drug tests are simple, urine based immunoassay tests. eCollection 2022 Apr. This acid-reducing medication is less effective when combined with certain food and drinksbut that doesnt mean you have to cut out caffeine entirely. When consumed in large quantities (such as in a poppy seed bagel or muffin), the tiny black seeds might cause a false positive drug result for opioids. The https:// ensures that you are connecting to the It didn t how much can lifestyle changes lower blood pressure say who the roasted whole sheep belonged to, So Al grabbed this guy, and the final result was very unexpected. RELATED: Benadryl details | Doxylamine details. Metformin is a drug commonly used to reduce the blood sugar of diabetic patients. These meds include pseudoephedrine, labetalol, bupropion, trazodone, and chlorpromazine. Pract Pain Manag. 3. The PubMed wordmark and PubMed logo are registered trademarks of the U.S. Department of Health and Human Services (HHS). Brahm NC, Yeager LL, Fox MD, Farmer KC, Palmer TA. Category: Medical. Liquid chromatography/tandem mass spectrometry (LC-MS/MS) is an alternative to GC-MS and may be more time efficient. U.S. Pharmacist. Generally, there are two methods for drug testing using urine samples; they are the definitive and presumptive drug monitoring tests. Brompheniramine has the potential to cause a false positive for amphetamines on urine drug screenings. 2023 SingleCare Administrators. https://www.cdc.gov/nchs/fastats/drug-use-illicit.htm, https://www.samhsa.gov/workplace/resources, https://www.samhsa.gov/sites/default/files/workplace/2010GuidelinesAnalytesCutoffs.pdf, https://www.federalregister.gov/documents/2017/01/23/2017-00979/mandatory-guidelines-for-federal-workplace-drug-testing-programs, https://accesspharmacy.mhmedical.com/content.aspx?sectionid=210267566&bookid=2569#216818178, Amantadine, aripiprazole, atomoxetine, brompheniramine, bupropion, chlorpromazine, desipramine, DMAA, ephedrine, fluoxetine, labetalol, metformin, ofloxacin, phentermine, phenylephrine, phenylpropanolamine, promethazine, pseudoephedrine, ranitidine, selegiline, thioridazine, trazodone, nonprescription nasal antihistamine/decongestant inhalation, Baby wash products, dronabinol, efavirenz, ibuprofen, lamotrigine (on screenings for synthetic cannabinoids), naproxen, niflumic acid, proton pump inhibitors, Ambroxol, amitriptyline, benzphetamine, bupropion, buspirone, cephradine, chlorpromazine, desipramine, diltiazem, doxepin, fentanyl, fluoxetine, haloperidol, imipramine, labetalol, metoclopramide, prochlorperazine, risperidone, sertraline, thioridazine, trazadone, verapamil, ergonovine, lysergol, brompheniramine, imipramine, methylphenidate, fentanyl, sertraline, Diphenhydramine, doxylamine, chlorpromazine, clomipramine, doxylamine, quetiapine, thioridazine, verapamil, Amisulpride and sulpride, codeine, dextromethorphan, diphenhydramine, dihydrocodeine, morphine, methadone, morphine-3-glucuronide, creatinine, dihydrocodeine, levofloxacine, ofloxacine, morphine, naloxone, ofloxacin, petanzocine, psychotropic drugs, quetiapine, rifampicin, tapentadol, tramadol, verapamil, quinolones, quinine, Dextromethorphan, diphenhydramine, doxylamine, ibuprofen, imipramine, ketamine, lamotrigine, MDPV, meperidine, thioridazine, tramadol, venlafaxine. Esposito concluded that the >20% d-methamphetamine guideline is still relevant and appropriate based on their findings.. New York, NY: Pharmacia & Upjohn Company, a Division. What causes a false positive? Thats because the chemical structure of phentermine is similar to that of an amphetamine, so if youre taking the drug, it is likely to appear as a positive result on a 5-panel urinalysis. )