Rite Aid and other US pharmacies could soon sell a drug derived from cannabis.

The Food and Drug Administration on June 25 approved Epidiolex, a treatment for epilepsy created by British drugmaker GW Pharmaceuticals (GWPH). The Drug Enforcement Administration has 90 days to schedule the medication, and it is widely expected to allow doctors to prescribe it.

That will open the cannabis industry to mainstream pharmacies and medical practitioners.

Rite Aid (RAD) told CNNMoney it would sell Epidiolex once the DEA schedules it.

"Rite Aid pharmacists fill prescriptions in accordance with all state regulations and laws as well as those set forth by the DEA and FDA," said Rite Aid spokeswoman Ashley Flower. "Given that Epidiolex has received approval from the FDA, upon being rescheduled, Rite Aid expects to fill prescriptions for Epidiolex later this year based on availability."

Walgreens (WBA), CVS (CVS) and Walmart (WMT)did not immediately comment about their plans to fill Epidiolex prescriptions.

Stephen Schultz, vice president of investor relations for GW Pharmaceuticals, said the company expects to launch Epidiolex in the fall, pending scheduling from the DEA. He said it will be produced in the United Kingdom and exported to the United States.

Smaller, independent pharmacies would also be able to provide the medication, which is approved to treat both adults and children aged two and older.

"If it's possible to stock it and dispense it, we will do it," said Phil Kuhr, manager and pharmacist at Stoner Drug, a pharmacy in Hamburg, Iowa, that's been in business since 1896.

Related: Stoner Drug, serving small-town Iowa since 1896

Epidiolex is derived from cannabidiol, or CBD, an active chemical compound in marijuana that reduces the frequency of seizures. In clinical trials, some patients said they no longer had seizures.

CBD is different from marijuana's more well-known compound: tetrahydrocannabinol, or THC, which gets people high. Marijuana is considered a schedule 1 drug by the US government, putting it on par with heroin. It is a federal crime to buy and sell marijuana, although 10 states have legalized its recreational use.

DEA spokesman Melvin Patterson said the agency has no plans to reschedule or deschedule marijuana, though there is a "discussion" about rescheduling CBD.

But he said that won't affect Epidiolex's approval, since individual drugs often receive their own schedule.

In the 30 states where medical marijuana is legal, dispensaries already sell CBD treatments. The drugs can be prescribed for patients suffering from epilepsy, cancer, HIV, MS and chronic pain.

But dispensaries won't be selling Epidiolex or any future FDA-approved drug with CBD, according to Kris Krane, president and co-founder of 4Front, an advisory and investment firm that owns dispensaries.

He said that as an FDA-approved pharmaceutical, it can only be sold in stores that have pharmacy licenses.

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Dispensaries are licensed by state agencies, and can only sell products authorized within the state program.

Krane said that Epidiolex would probably be more expensive than CBD treatments within a state medical program, which typically costs $200 to $500 a month. But FDA-approved drugs are often covered by insurance, and state-authorized medical marijuana is not.

Schultz, of GW Pharmaceuticals, said the pricing will be set after the DEA scheduling.