Can Vyvanse Cause A Positive Amphetamine Drug Test?
In our latest question and answer, the pharmacist discusses why Vyvanse will cause a positive drug test for amphetamine.
I'm prescribed Vyvanse for ADHD, and I took a drug test for work and received a message saying that I tested positive for methamphetamine and amphetamine. I have never used meth! Could Vyvanse cause this? They said they would send it to the lab.
Oct 06, 2022- Vyvanse is converted in your body to dextroamphetamine, which will cause a positive result on a standard urine drug test for amphetamines.
- Vyvanse can occasionally cause a false positive for methamphetamine due to cross-reactivity of some drug tests, though this is not a direct result of the medication itself.
- If you test positive and are concerned about accuracy, ask your healthcare provider about more definitive testing methods like gas chromatography.
Answer
Vyvanse will certainly cause a positive test for amphetamine if you are taking a standard urinalysis drug test.
The active ingredient in Vyvanse is lisdexamfetamine, a prodrug of dextroamphetamine (d-amphetamine). A prodrug is simply a drug that requires metabolic activation to the active compound in the body.
In other words, after taking Vyvanse by mouth, lisdexamfetamine is converted to dextroamphetamine in the blood (due to the high hydrolytic activity of red blood cells). Dextroamphetamine is an 'amphetamine' and will produce a positive result on urine drug tests.
What About Vyvanse Causing A Positive Methamphetamine Result?
In terms of testing positive for methamphetamine, while taking Vyvanse, that is possible based on a problem with "cross-reactivity" on urine drug screenings. However, it is important to distinguish that one byproduct of methamphetamine metabolism in our bodies is amphetamine, and you therefore will test positive for amphetamine on a drug test if you are taking methamphetamine.
Some drug tests do specifically look for methamphetamine as the parent compound too. It has been reported that many drugs, (including amphetamine products, Wellbutrin, and Zantac for example) have been known to cause "false positives" for methamphetamine.
Urinalysis False Positives
The main factor that causes false positives is the drug tests themselves. The most commonly utilized tests are immunoassay tests, such as the EIA (Enzyme-Linked Immunoassay) test. They work by utilizing antibodies to react to specific drug compounds, such as methamphetamine. When a specified compound (e.g. meth) is present in a test urine sample, an antibody binds to it and produces a reaction. When a reaction occurs, it is recorded as a 'positive' result.
However, many times drugs that are NOT being tested for can occasionally react with the wrong antibody (i.e. 'cross react'), resulting in a 'false positive'. This may have happened in your case. There are more accurate and definitive ways to test for drug compounds (such as gas chromatography) and if those options are available, be sure to ask your doctor or testing facility if they can be utilized.
Final Words
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References & sources
Glossary — Terms in This Answer
- Prodrug
- A medication that is inactive when taken but gets converted into its active form inside your body.
- Lisdexamfetamine
- The active ingredient in Vyvanse that your body converts into dextroamphetamine.
- Dextroamphetamine
- A stimulant medication that is the active form your body creates from Vyvanse and will show up on drug tests as amphetamine.
- Cross-reactivity
- When a drug test antibody mistakenly reacts to a substance it wasn't designed to detect, causing a false positive result.
- Immunoassay
- A type of drug test that uses antibodies to detect specific substances in a urine sample.
- Enzyme-Linked Immunoassay
- A specific type of immunoassay test commonly used to screen for drugs in urine samples.
- Gas chromatography
- A highly accurate laboratory method for detecting and identifying specific drug compounds with minimal risk of false results.
- Hydrolytic activity
- The ability of red blood cells to break down and convert lisdexamfetamine into dextroamphetamine.
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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