OKLAHOMA CITY (AP) -- Attorney General Drew Edmondson says few Oklahomans are taking advantage of advance directives that allow people to make their wishes known if they're comatose or in a persistent vegetative state.

As a part of Palliative Care Week in Oklahoma this week Edmondson is encouraging residents to talk to family, friends and their doctors about their health care wishes and to put that in writing.

The state has an advance directive statute to allow Oklahomans make their wishes known if they become terminally ill or persistently in a coma, but Edmondson says it's unconstitutional.

The attorney general says the problem with the state law is it puts limits on a person's right to refuse food and water that's supplied artificially -- such as through an IV.

He says he's working to develop a law to protect patients' rights and is constitutional.