A showdown over how to legalize medical marijuana in Georgia appears more likely than ever, after Senate leaders signaled Friday that they want to restrict access to only a very limited trial program involving children with epilepsy.

It's a dramatic counterpoint to an expanded proposal passed overwhelmingly Wednesday by the state House. That plan, House Bill 1, would make it legal to possess limited amounts of medical marijuana with a doctor's prescription to treat more than half a dozen disorders including cancer, Parkinson's disease and sickle cell disease.

The dueling proposals bring to mind what happened last year, when the Senate used the legalization of medical marijuana as a wedge to move other bills and it died in the final minutes of the 2014 legislative session.

The Senate plan's sponsor, Sen. Lindsey Tippins, R-Marietta, was not immediately available for comment Friday. But supporters of legalization said the Senate's decision to pursue a separate bill worried them that the same thing could happen again this year.

"I applaud the Senate wanting to help kids with seizures. We share that desire," said state Rep. Allen Peake, R-Macon, who has led the House's efforts. But, he added, the House "passed a bill that could help half a million people. They're shortchanging a lot of citizens."

There is also a question of how the Senate proposal would help at least a dozen families who have already left Georgia seeking to use cannabis oil to treat certain seizure disorders in both children and adults — afflictions that can cause hundreds of seizures a day and often lead to death. The oil is harvested from the marijuana plant but does not create the high that recreational use of marijuana produces.

The Senate plan, which will be introduced Monday at the Capitol as Senate Bill 185, would restrict the oil's use to only a four-year research trial program conducted through the University System of Georgia. Only children under 18 suffering from epilepsy would be eligible, and they must either have been Georgia-born or have lived in the state for at least two years.

It seems designed to curry favor with Gov. Nathan Deal, who late last year announced plans to start clinical trials involving cannabis oil, including at the state’s Georgia Regents University. The Senate plan would formally legalize the university’s efforts, which started Dec. 30, and eventually could expand the university’s initial 50-patient trial.

The House plan has no age limits and would decriminalize the possession of up to 20 ounces of cannabis oil that contains no more than 5 percent of THC, the high-inducing chemical associated with marijuana use.

HB 1 would require patients to have a state registration card, which could only be granted by a physician for treatment of one of nine specific disorders: cancer; Crohn’s disease; fibromyalgia; Lou Gehrig’s disease (amyotrophic lateral sclerosis); mitochondrial disease; multiple sclerosis; Parkinson’s disease; seizure disorders; and sickle cell disease.