BATON ROUGE, La. — Louisiana is becoming the first state in the Republican-dominated Deep South to expand its Medicaid program, with more than 233,000 people already enrolled in the government-financed insurance coverage that began Friday.

Medicaid expansion fulfills one of Democratic Gov. John Bel Edwards’ main campaign promises, embracing the health law championed by President Obama after years of GOP stonewalling in Louisiana.

“I understand that this is a Southern state. It’s a conservative state, with a majority of the legislators Republican. But I’ve always said the idea of expanding Medicaid is not right versus left, it’s right versus wrong,” Edwards said.

Adults ages 19 to 64 with incomes up to 138 percent of the federal poverty level – about $16,400 for a single adult or $33,500 for a family of four – are eligible for the coverage through one of Louisiana’s Medicaid plans administered by managed-care companies.

Joyce Brock, a 62-year-old Wendy’s cashier, enrolled for the coverage and was looking for a primary care doctor to monitor her asthma and test her for diabetes. Uninsured, she had struggled to cover the costs of inhalers and other medication, whose costs she estimated at $300 a month. Medicaid expansion will help her pay for prescriptions and get checkups.

“I’ve been crying for Medicaid,” Brock said, signing up at a Baton Rouge clinic.

The Edwards administration estimates 375,000 people will get insurance from the expansion over the next year, 70 percent of them full-time workers in like food service, tourism and construction.