For the first time, the U.S. Drug Enforcement Administration has classified a cannabis-derived drug as suitable for medicinal use.

The DEA on Thursday morning gave a Schedule 5 classification to GW Pharmaceuticals' Epidiolex, an antiseizure drug for rare forms of pediatric epilepsy. Schedule 5 is the lowest of the classifications in which drugs are categorized, so the DEA believes Epidiolex has a low potential for abuse.

GW Pharma, a U.K.-based biopharmaceutical company, said it expected to have the drug on the market in about six weeks.

Epidiolex is a liquid formulation of highly purified cannabis-derived cannabidiol (CBD). Clinical trials were conducted at Children's Hospital of Philadelphia. The U.S. Food and Drug Administration approved the drug in June for treatment of seizures.

CBD is one of hundreds of cannabinoids produced by the marijuana plant. A large gray market of CBD products exists in the commercial realm.

Marijuana remains classified as a Schedule 1 substance by the federal government, meaning the DEA believes it has no medicinal use, a high potential for abuse, and is as dangerous as LSD and heroin.

"Now that Epidiolex has been approved by the FDA, it has a currently accepted medical use in treatment in the United States for purposes of the Controlled Substance Act (CSA)," wrote the DEA in a legal notice. "Accordingly, Epidiolex no longer meets the criteria for placement in Schedule 1 of the CSA."

Epidiolex contains less than 0.1 percent of tetrahydrocannabinol (THC), the compound in cannabis that causes feelings of euphoria, and is extracted from forms of cannabis that are legally classified as hemp. Other CBD products will remain on Schedule 1.

The DEA's decision was lauded and criticized.

"This shows there are potential medicinal benefits for cannabis-based therapeutics and shows there are clear regulatory pathways to create products that can be distributed at pharmacies," said Max Tuttleman, philanthropist and CEO of SMRT Industries, a holding company of cannabis businesses. "Others developing formulations can use these same pathways to bring their medicines to market."

Andrew Sacks, a Philadelphia lawyer who is cochairman of the Pennsylvania Bar Association's medical marijuana and hemp committee, said, "The DEA gives the permission for imported CBDs, so a U.K. company can make millions, and still prohibits similar products produced in the U.S.A. from being produced or sold. If not for the FDA, GW Pharma would not have gotten this far. Hemp and CBD's should be off the schedule completely."

The retail price of Epidiolex is high, about $32,500 a year, but GW said costs were in line with other brand-name antiepileptic drugs used to treat the same intractable conditions. With insurance, out-of-pocket costs per month could range from $5 to $200 a month..

"We are pleased that the DEA has placed Epidiolex in the lowest restriction schedule, because it helps ensure that patients with LGS (Lennox-Gastaut syndrome) and Dravet syndrome, two of the most debilitating forms of epilepsy, can access this important new treatment option through their physicians," said GW Pharma chief executive Justin Gover.