The Arizona Supreme Court will hear a case about how driving under the influence laws apply to medical marijuana users. Under current law, card holders can be charged with a DUI if any amount of the drug is present in his or her system. 

Last October, the Arizona Court of Appeals ruled the medical marijuana law doesn't protect users charged with driving under the influence while having any of the active marijuana metabolite THC in their systems.

Two medical marijuana cardholders who were charged with DUIs argued in court the law provides a partial legal shield if the drug was prescribed by a physician.

The court of appeals ruled physicians don't prescribe medical marijuana, they only certify a patient's medical eligibility.