Ohio regulators have proposed restrictions on how much medical marijuana a patient could buy that would be among the strictest in the nation.

Under Ohio’s medical marijuana law, patients with 20 medical conditions can buy and use marijuana if recommended by a doctor. The state’s program is slated to become operational in September 2018.

The Ohio State Board of Pharmacy this past week released draft rules detailing the allowable amounts, Cleveland.com reported (http://bit.ly/2lCVI1T ).

Regulators are proposing limiting supplies by a product’s amount of THC, the psychoactive ingredient in marijuana. Ohio would be the first of the 28 medical marijuana states to calculate limits this way.

“I think this is the right approach because we’re in the middle of the pack of states that have adopted this,” Steven Schierholt, executive director of the State Board of Pharmacy, told the Ohio Medical Marijuana Advisory Committee. “We’ve benefited from what other states have done and have the benefit of their successes and failures.”

Patients could buy and possess up to six ounces of plant material or marijuana products containing the equivalent amount of THC in a 90-day period. Patients could mix and match products, but the amount could not exceed a total 90-day supply.

Chris Lindsey, senior legislative counsel for pro-marijuana group Marijuana Policy Project, said dosage and supply are tricky limits for the state to set because doctors can’t prescribe how much a patient can consume.

The proposed rules would impose a $100 fee on each strain or dosage of a product, which would likely be paid by the product manufacturer.

Public comment on the proposal is being accepted through March 10. The rules will go through two more stages of review and comment before being finalized.