State officials from at least four Illinois agencies have come together in an effort to come up with draft medical marijuana rules, with the hope of presenting a final plan to state legislators in May, reported the Southern Illinoisan.

A spokesman for Gov. Pat Quinn’s administration told the newspaper that officials have met several times already.

“All agencies tasked with implementation are reviewing Illinois and other states’ laws to ensure a successful Illinois program that avoids some of the pitfalls and challenges faced by other medical cannabis programs,” spokesman Mike Claffey said in a statement.

Illinois became the 20th state to legalize marijuana for medical purposes after Quinn signed the bill, HB 1, in August.

The measure creates a four-year trial period during which medical marijuana can be prescribed. Under the law, those with specific medical conditions, such as cancer, multiple sclerosis, and HIV/AIDS, can receive up to 2.5 ounces of marijuana every two weeks with a doctor's prescription.

Some 60 dispensaries and 22 marijuana cultivation centers across Illinois will be regulated by the Illinois Department of Agriculture, Department of Health, and Department of Financial and Professional Regulation.

The law goes into effect January 1.