Patients Using Sativex Spray Could Test Positive for THC in Roadside Drug Tests | Research

The takeaway

Patients taking Sativex (THC/CBD mouth spray) tested positive for THC on roadside screening tests within 2-3 hours of use, with very high oral fluid concentrations.

Read this if you use prescribed cannabis products and want to know how they affect roadside drug tests.

Oral fluid THC exceeded 5,356 ng/mL shortly after Sativex dosing

What the researchers found

After Sativex dosing, oral fluid contained very high concentrations of both THC and CBD. The primary Australian roadside screening test (DrugWipe II Twin) often gave false negative results even when THC concentrations were high. However, the secondary confirmation test (Cozart DDS) correctly identified THC in all Sativex-treated patients.

THC and CBD concentrations were extremely elevated shortly after dosing (over 5,356 ng/mL THC and over 3,826 ng/mL CBD) and remained detectable (over 67.6 ng/mL) two hours after administration. The average THC/CBD ratio across positive samples was 1.10, reflecting the 1:1 composition of Sativex.

While the THC/CBD ratio could theoretically distinguish Sativex use from recreational cannabis (which would have much higher THC relative to CBD), this distinction would not work if a patient used both Sativex and non-medicinal cannabis.

Why it matters

As medicinal cannabis products become more widely prescribed, patients face the real-world problem of testing positive on roadside drug tests. This study demonstrates that legitimate Sativex users will likely test positive for THC in oral fluid tests, raising legal and practical concerns for patients who drive.

The numbers in context

Low dose: 5.4 mg THC. High dose: 21.6 mg THC. Peak oral fluid THC: >5,356 ng/mL. Peak CBD: >3,826 ng/mL. THC/CBD ratio: 1.10 (RSD 19.9%). Detectable for 2+ hours. DrugWipe often gave false negatives; Cozart correctly identified all positive cases.

How the study worked

This was a double-blind, placebo-controlled pilot study. Patients received either Sativex or placebo at two dose levels: low (5.4 mg THC) and high (21.6 mg THC). Oral fluid was tested before dosing and at intervals up to 2 hours after dosing using two roadside screening devices and confirmatory LC-MS/MS analysis.

What this study cannot tell us

This was a small pilot study. Oral fluid concentrations immediately after oromucosal spray application may be artificially elevated due to direct oral contamination rather than systemic absorption. The 2-hour monitoring period may not have captured the full detection window. Only two screening devices were tested.

How to read the evidence

This is a double-blind, placebo-controlled pilot study with confirmatory laboratory testing, providing moderate evidence on the pharmacokinetic question.

When this study was published

Published in 2014. Roadside drug testing policies and medical cannabis legislation have continued to evolve since.

The bigger picture

Roadside drug testing policies were designed before medicinal cannabis became widely prescribed. This study highlights a gap between drug testing technology and the reality of legitimate medical use, creating a situation where lawfully prescribed patients may face legal consequences for driving.

Questions still open

Should roadside testing protocols include medical cannabis exemptions? Can THC/CBD ratios reliably distinguish medicinal from recreational use in practice? How long after Sativex use should patients wait before driving?

Common questions

What is Sativex?

Sativex is a prescription mouth spray containing roughly equal parts THC and CBD, approved in several countries for treating spasticity in multiple sclerosis. It is sprayed under the tongue or inside the cheek.

Why did the primary roadside test miss positive cases?

The DrugWipe II Twin, the primary screening device used in Australian roadside testing, gave false negative results in many cases despite very high THC levels. This appears to be a sensitivity issue with that specific screening device.

Read the original research

The detection of THC, CBD and CBN in the oral fluid of Sativex® patients using two on-site screening tests and LC-MS/MS.

Forensic science international, 238, 113-9

View on PubMed ↗Publisher’s paper ↗

Citation

Molnar, Anna; Fu, Shanlin; Lewis, John; Allsop, David J; Copeland, Jan. (2014). The detection of THC, CBD and CBN in the oral fluid of Sativex® patients using two on-site screening tests and LC-MS/MS.. Forensic science international, 238, 113-9. https://doi.org/10.1016/j.forsciint.2014.03.004