Can Lexapro Cause False Positives on Drug Screens?
No, escitalopram (Lexapro) is not documented to cause false-positive results on standard urine drug screens based on available evidence.
Understanding the Evidence
The available literature does not identify escitalopram as a cause of false-positive drug screen results. While the research evidence discusses citalopram/escitalopram in the context of alcohol treatment studies 1, there is no mention of these medications causing cross-reactivity with standard immunoassay drug testing panels.
Known Causes of False Positives
Standard immunoassay drug tests are susceptible to cross-reactions that can produce false-positive results 2. However, escitalopram is not among the documented culprits:
Amphetamine False Positives:
- Bupropion is the most frequent cause of false-positive amphetamine screens, accounting for 41% of unconfirmed positive amphetamine results in one study 3
- Pseudoephedrine in over-the-counter cold medications can cause false-positive amphetamine results 2
- Aripiprazole (an antipsychotic) has been reported to cause false-positive amphetamine screens 4
Other Common False Positives:
- Fluoroquinolone antibiotics can cross-react with opiate immunoassay screens 5
- Carbamazepine can cause false-positive tricyclic antidepressant results 6
Clinical Implications
When interpreting drug test results in patients taking escitalopram:
- Know the patient's complete medication history before interpreting results, as many medications can cause false positives 2
- Discuss unexpected positive results with laboratory personnel or toxicologists before making clinical decisions 5, 7
- Request confirmatory testing using gas chromatography-mass spectrometry (GC-MS) when results are unexpected or will impact patient management 5, 2
- Understand your testing panel's limitations, as standard panels may not detect many substances and have varying sensitivities 5
Important Caveats
- Many providers have inadequate training in interpreting urine drug test results, and incorrect interpretation can have severe consequences 5, 7
- Establishing a working relationship with your local toxicologist is recommended for consultation on complex results 5, 7
- The consequences of false-positive results can be severe, including loss of child custody or legal implications 7