LANSING, Mich. – A Michigan judge will hear a lawsuit filed against the state by major pharmaceutical companies who are fighting a plan to limit the drugs prescribed to Medicaid patients.

The suit is one of a handful filed by the Pharmaceutical Research and Manufacturers of America, an industry trade group opposed to states’ efforts to curb skyrocketing drug costs.

Other suits have been filed by the Washington-based trade group in Florida, Maine and Vermont. All are being closely watched by states eager to lower their drug expenditures.

Last week, U.S. District Judge David McKeague decided the Ingham County Circuit Court would rule on whether Michigan had the legal authority to put the plan in place. Hearings are scheduled to begin Jan. 7.

After the state court decides the case, McKeague said he will consider the issue of whether the plan violates the U.S. Constitution because it allows one state to regulate drug sales differently from other states. McKeague said that was the only issue in the lawsuit that needed to be considered by a federal court.

There was a disagreement between the two sides over whether the case should be heard in state or federal court. The Michigan Department of Community Health had asked a federal judge in Lansing to hear the case.

Drug companies sued the state Nov. 30 over its decision to cut costs by limiting the drugs doctors may prescribe to the state’s 300,000 Medicaid fee-for-service patients.

The state developed a list of drugs that must be given preference by doctors. Manufacturers were told to give discounts or risk being left off the list.

Starting Jan. 14, doctors wishing to prescribe a drug that isn’t on the list must call a state technician for permission. Approval will be granted only if the drug is medically necessary.

The list does not include several well-known drugs such as Ritalin, prescription Tylenol and the arthritis painkillers Vioxx and Celebrex.

The lawsuit pits the state against some businesses with a large presence in Michigan, including New York-based Pfizer Inc. and Peapack, N.J.-based Pharmacia Corp.