Can Trazodone Cause A False-Positive For Amphetamines?
In our latest question and answer, the pharmacist discusses if trazodone can cause a false-positive drug test for amphetamines.
Hi, I took some trazodone for the first time and have a drug test tomorrow. Will it pop up for amphetamines if it was a one-time use?
Nov 02, 2022- Trazodone has been reported to cause false-positive results for amphetamines on urine drug screenings, though how often this happens is not well documented. Taking trazodone does not mean you will test positive for amphetamines, as it is only a possible interference. Tell your drug tester about all medications you are taking before your test so a false positive can be addressed if it occurs.
Answer
Trazodone has been reported to cause 'false positives' for amphetamine on urine drug screenings, but just how common this is hasn't been reported.
It is important to note that just because you take trazodone, that doesn't mean your drug test for amphetamines will come back positive. It simply has been reported as a possible drug that can interfere with these tests.
Just in case a false positive does happen, be sure to tell your tester of all the medications you take before you get your test done.
Trazodone False-Positives
As mentioned, trazodone has been reported to cause false-positive results for amphetamines on urine drug screenings.
One of the most cited studies discussing urine drug screenings had this to say:
Results of amphetamine assays are often positive among patients taking prescription stimulants for attention deficit and hyperactivity disorder, for narcolepsy, and as anorexiants because many of these stimulants contain amphetamines. Many psychotropic medications, such as bupropion, phenothiazines (eg, chlorpromazine, promethazine, and thioridazine), trazodone, and TCAs (desipramine and doxepin), have been reported to interfere with immunoassays.
Another study stated that it was not uncommon that trazodone can interfere with these tests:
At our institution, false-positive amphetamine results occur not infrequently in patients taking trazodone with at least 8 trazodone-associated false-positive results during a single 26-day period. Laboratories should remain cognizant of this interference when interpreting results of this assay.
Why Do False-Positives Happen?
While there are several types of urine drug screenings available to testers, the most commonly used ones are of the immunoassay variety. These tests rely on antibodies to react with specific drugs (or drug metabolites) in a given sample.
While these tests have several advantages, such as being relatively inexpensive and providing fast results, they are prone to errors. Sometimes, antibodies can react with the wrong drug or metabolite, which results in a false-positive reading.
How Long Does Trazodone Stay In Your System?
You mentioned in your question that you took trazodone yesterday. Based on the known half-life of the drug (around 10 hours), it most certainly is still in your system.
It generally takes around 5 half-lives to completely metabolize a drug, so it will still be in your system for 2-3 days after your last dose.
Tell Your Tester Of All The Drugs You Are Taking
It is very important to let whoever is doing your drug test know all the medications you are taking.
Drugs that can affect immunoassay urine drug screenings are well documented. If a false-positive result does occur, having discussed everything you are taking beforehand can be extremely helpful in being able to have the opportunity to take another test.
Final Words
I hope you found this answer helpful! Be sure to reach back out if anything else comes up.
References & sources
- The trazodone metabolite meta-chlorophenylpiperazine can cause false-positive urine amphetamine immunoassay results — https://pubmed.ncbi.nlm.nih.gov/21740694/
- False-Positive Interferences of Common Urine Drug Screen Immunoassays: A Review — Oxford Academic
- Commonly prescribed medications and potential false-positive urine drug screens — PubMed
- Urine Drug Screening: Practical Guide for Clinicians — Mayo Clinic Proceedings
Glossary — Terms in This Answer
- False positives
- Test results that incorrectly indicate the presence of a drug when that drug is not actually present in the sample.
- Urine drug screenings
- Tests that analyze urine samples to detect the presence of drugs or their byproducts in the body.
- Amphetamine
- A type of stimulant drug that increases alertness and energy, sometimes prescribed for medical conditions like ADHD.
- Psychotropic medications
- Drugs that affect brain function and are used to treat mental health conditions like depression and anxiety.
- Immunoassays
- Laboratory tests that use antibodies to detect and measure specific substances in a sample.
- Drug metabolites
- Chemical compounds formed when the body breaks down and processes drugs.
- Half-life
- The time it takes for the body to reduce the concentration of a drug in the system to half its original amount.
- Metabolize
- The process by which the body breaks down and eliminates drugs and other substances from the system.
Dr. Brian Staiger, PharmD
Doctor of Pharmacy, board certified clinical pharmacist (BCPS), American Herbalist Guild, Medication Therapy Management certified
Brian Staiger, PharmD, BCPS, is a licensed pharmacist with more than 13 years of experience across retail pharmacy, clinical pharmacy, medication safety, pharmacy program development, and healthcare administration. He is the founder of HelloPharmacist.com, where he helps patients...
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