A Kansas cancer patient is serving a two-day jail sentence for driving under the influence of a drug. The drug in question is a synthetic version of THC that she consumed in the form of Marinol, an FDA-approved treatment for the nausea and vomiting caused by cancer chemotherapy.

KAKE, the ABC station in Wichita, reports that Angela Kastner, a grandmother who was diagnosed with colorectal cancer five years ago, pleaded no contest to the DUI charge, even though, according to her pharmacist, there was not enough THC in her blood to impair her ability to drive. Under Kansas law, it is a Class B misdemeanor, punishable by up to six months in jail, to operate a motor vehicle while "under the influence of any drug or combination of drugs to a degree that renders the person incapable of safely driving a vehicle." A conviction requires proof that the drug "rendered defendant incapable of safely driving a vehicle" or that the defendant "was a habitual user of a narcotic, hypnotic, somnifacient or stimulating drug."

Kastner could be described as a "habitual user" of THC, but only because her doctor prescribed it to help her tolerate the side effects of chemotherapy. According to a summary of the Kansas DUI law from the National Highway Traffic Safety Administration, habitual users of a drug with any amount of it in their systems are automatically deemed to be impaired, although there is no logical or scientific basis for that "zero tolerance" rule.

"I had…Marinol in my system that the doctors in Oklahoma gave me to fight cancer," Kastner told KAKE. She worried that she would "miss my chemo tomorrow," although a spokesman for the Sedgwick County Sheriff's Office said "we take the care of our inmates very seriously," suggesting that arrangements could be made for Kastner's treatment.

Kastner said she went public with her story as a warning to other cancer patients who take Marinol. "I feel sorry for the next cancer patient who has to go through anything I have had to go through," she said. "They shouldn't have to do this at the end of their life."