A person may be required to take a urine test that screens for illicit drug use for a number of reasons. Some companies request that employees take drug tests to ensure workplace safety. People who have been convicted of drug related crimes are often screened to detect whether drug use is ongoing. Whenever a person is about to undergo such a test, they may experience anxiety even if they haven't consumed any illicit substances, due to the existence of false positives on drug tests. A number of legal medications can cause false positive results on a urine drug screen.
Vicks Inhaler
Those who have used a Vicks inhaler may have a false positive for amphetamine and methamphetamine. Vicks inhalers are sold over the counter and are used to relieve nasal congestion from colds or allergies. According to an October 2006 article in "The Journal of Family Practice," false positives related to Vicks inhalers typically occur when the patient has doubled the recommended dosage.
Sertraline
When an initial urine drug screen indicates the presence of illicit drugs, a more definitive test called gas chromatography mass spectrometry is used to confirm the accuracy of the urine screen results. When researchers at the Naval Medical Center Department of Psychiatry detected a pattern of false positive urine screens indicating benzodiazepine abuse, they launched a study investigating the connection between these false positive tests and the legitimate use of the drug sertraline, an antidepressant also known as Zoloft. Their study, published in the July 2009 edition of the journal "Psychiatry (Edgmont)" indicated that sertraline caused 26 percent of false positive urine tests results for benzodiazepines.
NSAIDs
The use of nonsteroidal anti-inflammatory drugs, or NSAIDs can result in false positives for amphetamine and cannabinoid, the active compound in marijuana. NSAIDs are used in the treatment of swelling, pain and inflammation and are widely available over the counter. Ibuprofen is a commonly used NSAID that is sold under brand names that include Motrin, Advil, Nuprin and Aleve. Aspirin and naproxen are also common NSAIDs. Prescription forms of NSAIDs include Anaprox, Naprosyn and Orudis.
"The Journal of Family Practice" specifically cites oxaprozin, an NSAID that works by reducing hormones that cause inflammation, as a cause of false positives for benzodiazepine
Flouroquinolone
Flouroquinolones are antibiotics, used to treat bacterial infections such as bronchitis and gonorrhea, according to Drugs.com. The flouroquinolone drugs ofloxacin and levofloxacin are particularly prone to causing false positive test results indicating the use of opiates.
References
- The Journal of Family Practice"; What Common Substances Can Cause False Positives on Urine Screens for Drugs of Abuse; Dr. Chris Vincent et al.; October 2006
- "Psychiatry"; False-Positive Urine Screening for Benzodiazepines: An Association with Sertraline?; Kevin M. Nasky, DO et al; July 2009
- Drugs.com: Ofloxacin
- "Journal of Analytical Toxicology"; Enantiomeric Separation and Quantitation of (+/-)-Amphetamine, (+/-)-Methamphetamine, (+/-)-MDA, (+/-)-MDMA, and (+/-)-MDEA in Urine Specimens by GC-EI-MS After Derivatization with (R)-(-)- or (S)-(+)-Alpha-methoxy-alpha-(trifluoromethy)phenylacetyl Chloride (MTPA); September 2004
- NetWellness: Addiction and Substance Abuse: Drug Testing
