Doctors who prescribe long-term antibiotic therapy for tick-borne Lyme disease are now at risk for licensing sanctions in Minnesota, a sign that many leaders in the profession regard the therapy as discredited.

The Minnesota Board of Medical Practice earlier this week lifted its decadelong moratorium on such actions because of research suggesting that long-term antibiotic therapy offers no benefits over the short-term therapy that most patients receive when their Lyme cases are diagnosed.

Whether the change will result in a wave of disciplinary actions is unclear, because the board only investigates complaints and some doctors might have dropped this form of treatment, said Ruth Martinez, the board’s executive director. “It’s kind of hard to know because we’re a complaint-driven process,” she said.

Antibiotic therapy for chronic Lyme symptoms became a medical and political controversy in Minnesota in 2010, after the Infectious Diseases Society of America discouraged the practice. The society cited a lack of evidence that it helps, as well as concern that overuse of antibiotics would give rise to drug-resistant bacteria strains.

Some Lyme experts sought legislation to protect the practice because they worried that the society’s stance would give the medical board justification to penalize doctors who believed the treatment worked. The compromise was the board’s moratorium, which it reviewed and extended in 2014, until research adequately addressed the question.

The board this week decided to lift the moratorium based largely on a Dutch study published in 2016 in the New England Journal of Medicine that showed that long-term antibiotic therapy offered no more relief from chronic Lyme symptoms than placebo pills.

Minnesota is a Lyme hot spot due to the prevalence of black-legged (or deer) ticks that carry the bacteria that causes it. The state reported 950 cases last year, plus another 591 probable cases that weren’t confirmed by lab tests.

Known for the bull’s-eye rash that often appears at the infection site, Lyme disease causes fatigue, joint pain and other symptoms. Most patients recover with standard antibiotics within a few weeks, but some suffer lingering symptoms.

The U.S. Centers for Disease Control and Prevention also discourage long-term antibiotic therapy for treatment of these chronic symptoms, noting research that it can cause complications, including an increased risk of future infectious diseases.

While no one spoke in opposition to the board’s decision at its latest meeting, the decision upset some Lyme advocates.

Dr. Elizabeth Maloney of Wyoming, Minn., has created online training for physicians regarding Lyme disease and serves on the treatment subcommittee of the federal Tick-Borne Disease Working Group. She pointed to a separate study showing that long-term antibiotics at least offered benefits to a subgroup of Lyme patients with persistent fatigue.

Doctors with experience in treating Lyme should still be able to use this treatment option when others aren’t working, she said, but she worries that they will now be afraid to do so.

“It becomes an access-to-care issue,” she said, “for these very sick patients.”