Drug TestA common form of drug testing is in the form of a urine drug screen (UDS), also known as a urinalysis. A drug screening is often requested by employers as a term of employment. A urine sample is evaluated to determine whether or not a specified drug is present and if the sample was collected appropriately by documenting appearance, temperature, pH, concentrations, and the reactions of the sample to testing agents. 

The Department of Health and Human Services (DHHS) have established the acceptable levels of each drug in a person that will determine a positive result regarding the workplace. A test result below these cutoffs is considered a negative result. These results are determined only for adults regarding the workplace and would not apply for children.

Proton Pump Inhibitors, which includes Prilosec (omeprazole), have been reported in studies to cause false positives for amphetamines.

The drugs that will cause a positive result for amphetamine urinary analysis include:

  • Phentermine
  • Tranylcypromine
  • Propranolol
  • MDA (methylenedioxyamphetamine)
  • MDEA (ethylenedioxyethylamphetamine)
  • MDMA (methylenedioxymethamphetamine)
  • hydroxybupropion
  • Erythro-dihydro bupropion
  • Amantadine
  • Benzphetamine
  • Chlorpromazine
  • NSAIDs
  • Proton pump inhibitors (PPIs) (e.g. omeprazole)

For the full list see Table

It is important that if you do receive a false positive result to request a test that is more accurate to confirm the results (such as by liquid chromatography-mass spectrometry). Make sure to give your doctor a full list of your medications to ensure that there is no cross reactivity between your medications. 

An ongoing study conducted by the FDA reports on the occurrence of false positives results for drug screens in patients taking omeprazole. They found that false positive results were more common in females, patients between the ages 20 to 29, had been taking omeprazole for less than a month, patients also taking escitalopram, and patients with cystic fibrosis. This being said, only a small number of patients have reported a false positive regarding omeprazole, 35 people out of 174,713 reported this when taking omeprazole.  


Omeprazole (Prilosec) is an antacid medication that is commonly used to treat and prevent the recurrence of duodenal ulcers, gastroesophageal reflux disease (GERD), and to reduce acid in the stomach. The onset of action after taking omeprazole begins within one hour, with the maximum effect taking place within two hours. Omeprazole is broken down by the metabolites and is then excreted as at least six different metabolites in the urine.


In summary, there have been a limited number of cases reported for a false positive drug screen for amphetamines in patients taking omeprazole.

  • There have been reports of omeprazole causing false positives on urine drug tests, but it appears uncommon.
  • Request for another drug screening that is more accurate to confirm the results.
  • Talk to your doctor regarding the medications that you are taking to determine if there may be an interaction with the test.