Are Drug Tests Able To Detect Methamphetamine And Amphetamine?

In our latest question and answer, the pharmacist discusses whether or not a urine drug test can distinguish between methamphetamine and amphetamine.

Jul 02, 2018

jam asked

Will a drug test show just as an amphetamine, not methamphetamine?

Answer

Most commonly utilized urine drug tests can distinguish between amphetamine and methamphetamine. According to the Urine Drug Screening: Practical Guide for Clinicians from Mayo Clinic Proceedings:

Most amphetamine assays are designed to detect amphetamine, racemic compounds (eg, dextroamphetamine, methamphetamine), and illicit analogues (methylenedioxyethylamphetamine, methylenedioxyamphetamine, and methylenedioxymethylamphetamine [MDMA])

It is important to note that if you test positive for methamphetamine, amphetamine will be detected as well since it is an active metabolite of methamphetamine metabolism.

In most cases, methamphetamine is detectable in the urine for up to 48 hours since last use.

Methamphetamine False Positives

Urine drug screenings are subject to false positives and there are various substances that have been reported to cause a false-positive for methamphetamine. They include:

  • Amantadine
  • Brompheniramine
  • Bupropion
  • Chlorpromazine
  • Chloroquine
  • Desipramine
  • Doxepin
  • Labetalol
  • Methylphenidate
  • Phenylephrine
  • Promethazine
  • Pseudoephedrine
  • Ranitidine
  • Selegiline
  • Thioridazine
  • Trazodone
  • Trimethobenzamide
  • Venlafaxine
  • Vicks inhaler (l-methamphetamine)


Using an over the counter nasal inhaler that contains l-methamphetamine (also known as levomethamphetamine or levmetamfetamine) is likely to cause a false positive if you use it consistently. L-methamphetamine is essentially one-half of the methamphetamine molecule (the other being d-methamphetamine) and has very mild, if any, stimulant effect. Nevertheless, most urine drug tests are unable to differentiate between methamphetamine, d-methamphetamine and l-methamphetamine.

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