Can Trazodone Cause A False-Positive For Amphetamines

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 use 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.