The change has alarmed patient advocates and civil liberties groups, who say it effectively criminalizes lawful medical marijuana use. Under the new statute, any detectable amount of tetrahydrocannabinol—the psychoactive compound in cannabis—can serve as the basis for a DUI charge, regardless of whether the driver shows signs of intoxication.

"This law turns patients into criminals for taking medicine their doctor recommended," said one Oklahoma City attorney who represents medical marijuana cardholders. "THC can stay in the bloodstream for days or even weeks after use, long after any impairment has faded. A positive test tells you nothing about whether someone is safe to drive."

The measure arrives as Oklahoma's medical marijuana industry faces what observers describe as a freefall, with dispensary closures and regulatory uncertainty mounting across the state. Nearly 400,000 Oklahomans hold medical marijuana licenses, according to state data, making the new DUI standard one of the most far-reaching in the nation.

Critics point out that unlike alcohol, there is no scientifically established blood-THC threshold that reliably predicts impairment. Chronic users, in particular, can test positive for extended periods without experiencing any psychoactive effects. That scientific reality, opponents argue, makes the law ripe for uneven enforcement and wrongful prosecutions.

Supporters of the measure contend it closes a loophole and gives law enforcement a clearer tool to keep impaired drivers off the road. But civil rights advocates warn the law could lead to pretextual stops and disproportionately affect patients who rely on cannabis for conditions ranging from chronic pain to epilepsy.

"We're seeing a fundamental shift in how Oklahoma treats medical marijuana patients," said a spokesperson for a statewide patients' rights group. "People who followed the rules, got their licenses, and used cannabis responsibly are now at risk every time they get behind the wheel."

The law's implications extend beyond criminal penalties. A DUI conviction can jeopardize employment, housing, and professional licenses, creating lasting consequences for patients who have done nothing more than take a legally prescribed substance.

Legal challenges are expected. Attorneys say the statute's broad language—declaring THC a Schedule I drug without establishing an impairment standard—could conflict with the state's medical marijuana protections and raise constitutional questions about due process and equal protection.

For now, patients and their families are left navigating a confusing legal landscape. Some have begun altering their routines, avoiding driving for days after using cannabis, while others worry about being pulled over for unrelated reasons and subjected to a blood test.

"Oklahomans deserve laws based on science, not stigma," the patients' rights spokesperson said. "This law punishes people for being patients. That's not justice—that's a step backward."

As the state grapples with the fallout, the debate over how to balance road safety with patients' rights is likely to intensify in the coming legislative session. For the hundreds of thousands of Oklahomans who rely on medical cannabis, the stakes could not be higher.