Protonix (pantoprazole) can cause a false positive urine screening test for THC
March 5, 2015, 11:57 pm
13-Year-Old Girl With Recurrent, Episodic, Persistent Vomiting: Out of the Pot and Into the Fire. Felton D et al. Pediatrics 2015 Mar 2 [Epub ahead of print]
The package insert for Protonix (pantoprazole) states:
There have been reports of false positive urine screen tests for tetrahydrocannabinol (THC) in patients receiving protein pump inhibitors.
The source of these reports have not been clear, and no cases have previously been reported in the literature. This paper describes a 13-year-old girl who presented to hospital with an episode of recurrent cyclic vomiting syndrome, who was diagnosed with cannabinoid hyperemesis syndrome when a urine screening test was positive for THC. After a confirmatory gas chromatography-mass spectrometry test was negative for cannabinoids, the consulting toxicologist pointed out that the patient had received IV pantoprazole several hours before the urine specimen was obtained, and that the protein pump inhibitor was possibly responsible for the false positive test.
Although many clinicians are not aware of this effect, it is often mentioned in online drug discussion groups. This is the first case reported in the medical literature and — as the authors note — it is not clear if other protein pump inhibitors can also cause false positive tests for THC. The mechanism is not known.
H/T Nadia Awad (@Nadia_EMPharmD)