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An experimental epilepsy drug made from cannabis plants grown in England is complicating the medical marijuana debate in hospitals and statehouses.

Epidiolex is a nearly pure extract of cannabidiol, or CBD, with little of the tetrahydrocannabinol, or THC, that gets traditional pot users high. CBD products are the current rage in medicinal pot products, and activists fear that if the maker of Epidiolex manages to get FDA approval it could undercut the political momentum of the medical marijuana movement.

Anup Patel, a pediatric neurologist who oversees Epidiolex (pronounced eh'-pih-DYE'-uh-lehx) clinical trials at Nationwide Children's Hospital in Columbus, insists the drug contains the optimal known marijuana compound for treating seizures. He cited a study that found children can be hurt by using the whole plant.

Patel laments that children with epilepsy are being used — including during an unsuccessful Ohio ballot campaign last year — to push for medical marijuana legalization.

"People are mixing terms, mixing ideas," he said. "I'm not sure if that's just because of confusion, lack of knowledge or on purpose."

Karmen Hanson, the expert on marijuana policy for the nonpartisan National Conference of State Legislatures, said the two sides are at odds.

"The argument for traditional (whole-plant) medical marijuana is that people know what works for them — whether they're going to make their own concentrates or vape or combust, use flowered products, oils, you name it — so they want to protect their ability to do that," she said. "The other camp wants to see the head-to-head science, to give it more scientific validity, to elevate the products that are produced in terms of reliability and consistency."

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Patel is in Camp 2. He personally lobbied to get U.S. patients access to Epidiolex, which he said is effective, consistent and doesn't get users high.

About two years ago, Patel persuaded London-based GW Pharmaceuticals to give him enough of the medicine for a single patient, and his hospital's study was born. Last month, the company released positive results of late-stage testing. It plans to take Epidiolex to the U.S. Food and Drug Administration later this year.

The FDA has not yet found any botanical form of marijuana to be safe or effective to treat any disease or condition, spokesman Michael Felberbaum said. If approved, Epidiolex would be the first. Two synthetic cannabinoids — Marinol and Cesamet — are available.

FDA approval would allow any doctor to prescribe Epidiolex to any patient, and it would be covered by insurance. No law or ballot issue would be required.

Many medical marijuana activists fear Epidiolex approval will mark the beginning of Big Pharma's takeover of the marijuana plant, undercutting patients' ability to treat themselves as they see fit.

"We are not concerned with the pill (actually oil) form of a natural plant," said Wendy Johnson, who represents the Cannabis Safety Association in Ohio, where medical marijuana legislation was introduced last week. "In fact, it is looked upon very unfavorably and as a stumbling block on our way to whole plant."

Twenty-three states now have comprehensive medical marijuana and cannabis programs — but 17 others have chosen only to permit use of "low THC, high cannabidiol" products, mostly mom-and-pop cannabis oils or hemp extracts.

Since marijuana can't be legally grown in those 17 states, the narrower bills aren't much more than legal protections for people who are able to access the products, Hanson said. A low-THC, high-CBD strain of medical marijuana called Charlotte's web is grown in Colorado, for example, where marijuana is legal.

"They're worried about political pushback. That's it in the end," said John Hudak, a senior fellow at the Brookings Institution who studies marijuana law. "They're worried about an ad being run against them."

Tara Cordle, of Wheelersburg, Ohio, has a 10-year-old son, Waylon, who suffers from a severe form of epilepsy and is part of Epidiolex clinical trials at Nationwide Children's Hospital in Columbus.

She said she also wants Waylon to have access to the whole marijuana plant, even if it has risks. Cordle said it's difficult as a parent not to hope for a miracle cure — like the widely circulated story of 6-year-old Charlotte Figi seeing her seizures drop from 300 a week to three, giving her name to Charlotte's web.

She said Waylon takes 47 pills a day, pills that make him sweat, that give him diarrhea, that put him at risk of kidney stones or that promote early onset osteoporosis.

"I'm not afraid of doing a trial and error," she said, "because every seizure medication you put your child on is a trial and error."