Does Amitriptyline show up on a drug test? 

Does Amitriptyline show up on a drug test? 

Amitriptyline can show up on a drug test and can cause a false positive for Lysergic acid Diethylamide (LSD), a drug that alters the user’s perception, mood, and thought processes (1). Some antidepressants are associated with causing a false positive on preliminary urine drug screening. 

This is because of the cross-reactivity of antibodies used in the test with drug components which gives off a false positive. If we look at the chemical structure of Amitriptyline, it is not structurally related to controlled substances. 

These false positives are also produced because of the inaccuracy of the primary drug testing procedure and confirmatory tests should be conducted to confirm the findings. 

How long does Amitriptyline stay in your system? 

Amitriptyline has a half-life of about 25 hours, which is usually the time taken by the drug to reduce its initial concentration to half. The remaining concentration further reduces to half within the next 25 hours. 

The process continues until the entire drug is eliminated from your body, which could take up to 5-7 days. 

The time taken by the drug to wash out from your body depends on several other factors, like your age, weight, dosage strength, frequency, duration of treatment, any underlying health condition, and overall physiological well-being. 

How to avoid Amitriptyline showing up on a drug test? 

There is no easy way to prevent Amitriptyline from showing up on a drug test. It’s not recommended to stop the medication for the sake of your drug test as antidepressants are not stopped abruptly and you shouldn’t leave your treatment halfway. Antidepressants like Amitriptyline should be slowly tapered off.

Amitriptyline tablets can be cut in half if your doctor advises you to take half a dose. However, it should never be stopped cold turkey to avoid failing a drug test.

The best way to deal with this situation is to talk to your healthcare provider and submit your prescription prior to the test so that the test conducting authorities would know that you’re on a prescription for Amitriptyline, which is known for causing a false positive for LSD. 

However, if you’re going for more accurate testing procedures like Gas chromatography-Mass spectroscopy, dealing with false positives will not be a problem as this procedure delivers accurate results and is commonly used as a confirmatory drug test (2). 

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Alyson Schwebach, Jennifer Ball. Urine Drug Screening: Minimizing False Positives and False Negatives to Optimize Patient Care. US Pharm. 2013;38(12):1-6. Available at:


Ramoo B, Funke M, Frazee C, Garg U. Comprehensive Urine Drug Screen by Gas Chromatography/Mass Spectrometry (GC/MS). Methods Mol Biol. 2016;1383:125-31. doi: 10.1007/978-1-4939-3252-8_15. PMID: 26660182. Available from:

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