Supporters of legalizing marijuana for medical use in Missouri now have only one option this year – the ballot box.

That comes after the state House last week defeated House Bill 2213. In its original form, the measure would have allowed for medical cannabis centers in Missouri, which would have sold medical cannabis to patients with a "debilitating medical condition."

The House gave first-round approval to the bill last Wednesday, but only after further restricting marijuana prescriptions to terminally ill cancer patients in hospice care. That provision caused some supporters to change their votes, and the bill was defeated 66-87.

Right now, there are three proposed ballot initiatives that would legalize the medical use of marijuana in Missouri, all still being circulated for signatures. John Payne is political director for the group New Approach Missouri, which is sponsoring one of them.

"Our initiative really puts the power in the hands of doctors to say, 'Look, if you believe in your medical expertise -- you're the doctor -- that cannabis can help this patient medically who has a debilitating medical condition, then you should be allowed to make that recommendation to that patient,'" Payne said. "They should be allowed to legally use cannabis."

New Approach Missouri has until May 8 to turn in its petitions, and Payne says it already have more than enough signatures to qualify for the ballot.

"We filed our initiative back in October, (and) we now have about 210,000 signatures," he said. "The legal requirement is 168,000. You gather more than that, though, because you'll have some rate of invalidity … you assume that about 30 percent of those signatures are going to be invalid."

The proposed constitutional amendment would also levy a 4 percent tax on marijuana sales to fund health-care services for military veterans.

Several law enforcement groups have said at public hearings that legalizing medical marijuana use could lead to increased drug abuse. St. Louis Public Radio reached out to the Missouri Sheriffs Association and the Missouri Police Chiefs association for this story, but neither group has responded.

Follow Marshall Griffin on Twitter: @MarshallGReport