LANSING, MI - Changes related to Michigan’s medical marijuana law have been signed into law by Gov. Rick Snyder.

Some of the changes in measures signed Friday by the Republican governor alter the state’s voter-approved law from 2008. Others are related to that law.

House Bill 4851 tightens the definition of what will now be considered a "bona fide" physician-patient relationship in cases where medical marijuana is prescribed. Critics of the voter-approved law say it left too much room for abuse in allowing prescriptions for the drug. But medical marijuana supporters worry requiring a stricter doctor-patient relationship is among the provisions that could make the drug harder to get for legitimate patients.

House Bill 4834 makes multiple changes related to the issuing of medical marijuana registry identification cards, including some ID requirements.

House Bill 4853 relates to penalties for patients and caregivers who sell marijuana to people not legally allowed to have medical marijuana.

Employers would not be responsible for paying for their employees' medical marijuana treatments under Senate Bill 933. The measure relates to worker's compensation law.

There are other changes as well. Many of the bills were approved in the waning hours of the Michigan Legislature's 2011-12 session earlier this month.

Email Tim Martin at tmartin4@mlive.com. Follow him on Twitter: @TimMartinMI