Can Any Over the Counter Drugs Produce a Positive Benzodiazepine Reading on a Urine Test

Apr 2015

Question: What can crusade a faux-positive urine drug screening for benzodiazepines?

Respond: First introduced in the 1960s, benzodiazepines fall under the class of drugs referred to as sedative-hypnotics.¹ Traditionally, benzodiazepines have been used every bit anxiolytics, sedatives, muscle relaxants, allaying-hypnotics to treat alcohol withdrawal, likewise equally for other conditions.ⁱⁱ

Information technology is not uncommon, however, for physicians to prescribe benzodiazepines along with opioids for patients with chronic pain. When used in conjunction with opioid pain medications, benzodiazepines have been shown to raise pain relief, but the combination can be accompanied by increased risks for abuse and accidental overdose.³ Table one provides a list of generic and make names, parent drug half-lives, and speeds of onset for the ordinarily prescribed benzodiazepines.

Given the increasing and widespread utilize of benzodiazepines, both lonely and in conjunction with other medications, it is important for clinicians to use and empathise urine drug screen (UDS) to fully manage patients. UDS results tin assist optimize treatment by providing information most the presence of possibly illicit or non-prescribed drug use. However, clinicians need to be enlightened that simulated positive results can occur, necessitating confirmatory testing.

False-positive Screens

What could cause a faux-positive screen for benzodiazepines? A search of false positive benzodiazepine screenings showed the selective serotonin reuptake inhibitor (SSRI) sertraline (Zoloft, others) and the not-steroidal anti-inflammatory drug (NSAID) oxaprozin (Daypro, others) to be associated with, or possible causes of, these simulated-positive results.^4-7

Although the mechanism is unknown, sertraline, which is used to care for depression, obsessive-compulsive disorder, panic disorder, and anxiety, has been shown to increase levels of benzodiazepines when used in combination.² In addition, the package inserts for both oxaprozin and sertraline state that faux positive UDS results for benzodiazepines have been reported.^iv,5 Both package inserts state that initial screening tests result in a lack of specificity and that confirmatory tests, such equally gas chromatography/mass spectrometry (GC-MS) or liquid chromatography/mass spectrometry (LC-MS), should be used.

Nasky et al performed a 2-year retrospective examination of records identifying patients with positive benzodiazepine screenings that GC-MS confirmed were falsely positive.⁶ After identifying the patients, assays were cross-referenced with the chemist's database to see if patients with a confirmed false-positive benzodiazepine screening likewise had an active prescription for sertraline at the time of the initial screening. There were 522 positive UDS, 160 of which were after adamant by GC-MS to exist false positives. Sixty-ii of the 160 positive screens determined by cross-referencing with the pharmacy database also had an active benzodiazepine prescription. In the remaining 98 patients without an active benzodiazepine prescription, 26 (26.5%) of the total false positives had an active sertraline prescription.⁶

Metabolism

Well-nigh benzodiazepines undergo all-encompassing metabolism in the liver, and at that place have been reports of cross reactivity to these metabolites. Typical detection windows for benzodiazepines in the urine are 2 to 7 days, depending on the private benzodiazepine drug used and other factors, such as fourth dimension of terminal dose, drug half-life, route of administration, and individual differences in pharmacokinetics.^viii Post-obit administration, diazepam, for example, undergoes metabolism to yield the active metabolites nordiazepam and temazepam. Nordiazepam and temazepam and so are metabolized further to the final agile metabolic product oxazepam. Thus, the presence of nordiazepam, temazepam, and oxazepam together on a UDS is consistent with diazepam utilize.

One report compared the cross reactivity of oxaprozin with benzodiazepine assays using the fluorescence polarization immunoassay (Abbott FPIA), the enzyme multiplied immunoassay technique (Behring EMIT d.a.u.), and the cloned enzyme donor immunoassay (Boehringer Mannheim CEDIA DAU).^vii Negative screenings were established at baseline. Twelve individuals participated and supplied urine at baseline, 24 hours, 48 hours, and 72 hours following a ane-time dose of i,200 mg of oxaprozin. Baseline urine samples were bachelor from 4 participants; all screened negative for benzodiazepines. Oxaprozin cantankerous-reactivity was low (ane.vi%-2.5%) in the urine, merely at that place was evidence for false-positive benzodiazepine immunoassays afterward participants had a dose of oxaprozin. The results showed that 35 urine samples screened positive for benzodiazepines after 48 hours. The investigators used a GC-MS for confirmatory analysis. The study concluded that all positive urine screenings should exist confirmed by another assay to rule out potential imitation-positive results.⁷

With conflicting bear witness apropos the different benzodiazepine immunoassays, a 2014 study by Darragh et al, examined three different immunoassays specific for benzodiazepines to determine diagnostic accuracy.^nine This report targeted the loftier-sensitivity-CEDIA (HS-CEDIA) to look at its sensitivity and specificity compared to that of other traditionally used benzodiazepine immunoassays. The kinetic interaction of microparticles in solution (KIMS) assay was calibrated to a positive/negative cutoff of 100 ng/mL, the CEDIA and HS-CEDIA assays were calibrated to a positive/negative cutoff of 200 ng/mL. Out of 299 urine screenings, 141 were confirmed positive past LC-MS for 1 or more than benzodiazepines.⁹

The highest sensitivities were found with samples containing blastoff-hydroxyalprazolam and the lowest sensitivities were found with samples containing lorazepam and 7-aminoclonazepam. The HS-CEDIA assay demonstrated the highest sensitivity, at 78% (110/141), compared to 55% (78/141) with the CEDIA, and 47% (66/141) with the KIMS. Though the HS-CEDIA displayed college sensitivity compared to the other two, it still missed 22% (31/141) of benzodiazepine-positive samples; this was the everyman false-negative rate of the 3 immunoassays. This written report shows that even with a high sensitivity immunoassay such equally the HS-CEDIA, at that place are nonetheless discrepancies that could lead to false reports if not confirmed.^nine

Summary

The use of urine drug analysis in patient care settings is useful for clinicians. Although cross-sensitivity with oxaprozin is low, patients with a positive screening for benzodiazepines who also accept an active prescription for oxaprozin or sertraline should accept a confirmed GC-MS or LC-MS analysis. Information technology is not known whether sertraline or oxaprozin is a direct cause for false positive UDS, just the association cannot exist ruled out. Benzodiazepine-positive screenings and whatsoever other positive screening results should be confirmed using another technique to rule out false positives that otherwise may compromise therapy.

Last updated on: March 22, 2021

Enquire the Skilful: Lupus and Suicidal Ideation

phillipskins1938.blogspot.com

Source: https://www.practicalpainmanagement.com/resources/diagnostic-tests/ask-expert-false-positive-screen-benzodiazepines

Share this post