Can prazosin cause a false positive drug test

Journal of Analytical Toxicology: “Non-Smoker Exposure to Secondhand Cannabis Smoke. I. Urine Screening and Confirmation Results.”

Massachusetts Medical Society: “Urine Abstinence Testing And Incidental Alcohol Exposure.”

Mayo Clinic: “Urine Drug Screening: Practical Guide for Clinicians.”

National Center for Biotechnology Information: “Investigation of interference by nonsteroidal anti-inflammatory drugs in urine tests for abused drugs,” “False positive urine drug screens from quinine in tonic water,” “Cardiac Complications of Unwitting Co-injection of Quinine/Quinidine with Heroin in an Intravenous Drug User,” “The dextromethorphan defense: dextromethorphan and the opioid screen,” “A positive cannabinoids workplace drug test following the ingestion of commercially available hemp seed oil,” “Efavirenz use may cause false positive result for marijuana,” “Urine opiate screening: false-positive result with levofloxacin,” “An Overview of Clinical Pharmacology of Ibuprofen.”

National Institute on Drug Abuse for Teens: “What is Hemp?”

National Institute on Drug Abuse: “Misuse of Prescription Drugs,” “Benzodiazepines and Opioids.”

Operation Supplement Safety: “Weight-Loss Prescription Drugs: Phentermine.”

Pharmacokinetics in Psychiatry and Neurology: “Urine drug screens: Considerations for the psychiatric pharmacist.”

Substance Abuse and Mental Health Services Administration: “Clinical Drug Testing in Primary Care,” “Methadone.”

The Brookings Institution: “The Farm Bill, hemp legalization and the status of CBD: An explainer.”

U.S. National Library of Medicine: “Drug Testing,” “Quinine,” “Diphenhydramine,” “Dextromethorphan,” “Efavirenz,” “Amphetamine,” “Sertraline.”

University of Florida: “Germ-killing sanitizers could have effect on alcohol tests.”

American Alliance Drug Testing: “SAMSHA Guidelines -- Mandatory Federal Workplace Drug Testing Guidelines.”

Random drug testing is becoming more common in the workplace. Airline, railroad, trucking, pipeline, mass transit, and shipping industries do drug tests under US government law.

Private companies also do drug testing to keep health insurance costs down, improve productivity, lower absenteeism, and create a safe workplace.

Most companies do not hire people who test positive and also fire current employees who test positive.

Drug Testing in Schools

Drug testing is also becoming more common in schools that have students who do after school activities.

What They are Testing

The most common substances being tested for are:

Other substances that may be tested for are:

• Heavy alcohol use
• PCP (phencyclidine)
• Hallucinogenic drugs (LSD, peyote, mescaline, psilocybin, and ecstasy)
• Inhalants (fumes or gases that are inhaled for intoxication, such as glues, aerosols, butane, ether, nitrous oxide, and solvents)

Types of Drug Tests

Urine

Urine testing is the most popular type of test. It is simple, noninvasive, and very accurate. A part of marijuana called THC can be picked up in urine. Anabolic steroids can also be found through urine testing. The ability of the test to find these substances depends on how much was used and for how long.

Urine drug testing is widely used for testing for opioids and illicit drugs. Most of the time, a screening test with an immunoassay is used. It can find the parent drug and/or metabolite. It usually tests for marijuana, cocaine, opiates, PCP, and amphetamines.

Typically, the screening immunoassay detects the amount of drug present in urine above a predetermined cutoff concentration. So a substance may be there, but if the concentration of that drug is below the cutoff, the result will be negative. For more precise results, the confirmatory urine drug test is done by gas chromatography/mass spectrometry or high-performance liquid chromatography. This test is very specific and is often used when testing for the presence of a specific drug is needed.

Hair

Hair tests can give a semi-permanent record of drug use. Drugs circulating inside the body cling to the hair as it grows. So, if the drug was taken recently, it will be found in hair near the scalp. If the drug was taken in the past, the drug will be found in hair that has grown out.

Drugs cannot be washed out of the hair. This is not the same as drugs in smoke, which stick to the hair and can be removed with shampoo. However, products used on the hair might, at times, get in the way of test accuracy.

Hair testing has an advantage because it can detect drug use over longer periods of time (usually around 90 days). This test is available for home use.

Sweat

To test sweat, a bandage-like patch is put on the upper arm, midriff, or lower back to collect sweat. Contaminants from the environment cannot get through the patch from the outside, so the patch can be worn during normal activities. To prevent tampering, the adhesive plastic film cannot be reapplied after it is removed.

Residue

Residue tests are typically found in home testing kits that allow parents to test their children. The kit comes with a pad that picks up drug residue by swiping the pad on the child's belongings. The pad then is mailed to the manufacturer for testing. The major flaw with this test is that it cannot find out whether any drug residue found was left by the child under suspicion or by someone else.

Blood

Blood tests are the most accurate test, but are not used routinely in the workplace or school.

Saliva

A saliva test is a way to find out if someone has been using drugs within the past few days. This type of test can find many illegal substances, such as heroin and cocaine. But, it may be less reliable in detecting marijuana.

Breath

This involves exhaling into a hand-held machine to test for alcohol. Devices are available for home use. There are also one time use devices.

False-Positive Results

Sometimes, a drug test may report the presence of drugs when a person did not take any. This is not common, but no test is 100% accurate. Lab errors account for some of the mistakes, but most false-positives may be due to over the counter drugs and foods that can affect the test, such as:

*Large amounts of poppy seeds would need to be eaten to cause a positive test. Good tests can tell poppy seeds apart from opiates.

**Some people eat hemp oil because they believe it has nutritional benefits.

If you are mistakenly found positive for drug use, think about whether you have taken any substances known to cause false-positives.

Resources

National Institute on Drug Abuse
http://www.nida.nih.gov

US Food and Drug Administration
http://www.fda.gov

Canadian Resources

Alberta Health Services
https://www.albertahealthservices.ca

Health Canada
http://www.canada.ca

References

Detection and measurement of drugs. National Highway Traffic Safety Administration website. Available at: http://www.nhtsa.gov/people/injury/research/stateofknwlegedrugs/stateofknwlegedrugs/pages/3Detection.html. Accessed June 23, 2021.

Drug testing. Substance Abuse and Mental Health Services Administration—US Department of Health and Human Services website. Available at: https://www.samhsa.gov/workplace/resources/drug-testing. Accessed June 23, 2021.

Fact sheet: Drug testing in the criminal justice system. US Department of Justice website. Available at: https://www.ojp.gov/sites/g/files/xyckuh241/files/archives/ncjrs/dtest.pdf. Accessed June 23, 2021.

Hair drug tests. HealthStreet website. Available at: https://www.health-street.net/drug-tests/hair. Accessed June 23, 2021.

Substance test. Home Health Testing website. Available at: http://www.homehealthtesting.com/substance-test-c-21%5F53.html. Accessed June 23, 2021.

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