The Centers for Disease Control and Prevention (CDC) issued guidelines Tuesday that recommend primary care providers avoid prescribing opioid painkillers for patients with chronic pain, according to USA Today. The risks from opioids greatly outweigh the benefits for most people, the CDC says.

Primary care providers write nearly half of all opioid prescriptions, according to the CDC. The new guidelines are designed for primary care doctors who treat adult patients for chronic pain in outpatient settings. They are not meant for guiding treatment of patients in active cancer treatment, palliative care, or end-of-life care, the agency said.

Doctors who determine that opioid painkillers are needed should prescribe the lowest possible dose for the shortest amount of time, the guidelines state.

“More than 40 Americans die each day from prescription opioid overdoses, we must act now,” said CDC Director Tom Frieden, MD, MPH, said in a news release. “Overprescribing opioids—largely for chronic pain—is a key driver of America’s drug-overdose epidemic. The guideline will give physicians and patients the information they need to make more informed decisions about treatment.”

Frieden noted that many prescription opioids are as addictive as heroin, and poorly control chronic pain. He said doctors should first try therapies other than opioids, including exercise or non-steroidal anti-inflammatory medications, such as aspirin or ibuprofen.

Physicians are not legally required to follow the recommendations, the article notes. The guidelines provide advice on when doctors should begin or continue opioids for chronic pain, which types of opioids to choose, how long to prescribe them, and how to determine their risks.

Andrew Kolodny, Executive Director of Physicians for Responsible Opioid Prescribing, said the guidelines are a “game changer” that doctors are likely to follow. “For the first time, the federal government is communicating clearly that the widespread practice of treating common pain conditions with long-term opioids is inappropriate,” he said.