Existing law, the Knox–Keene Health Care Service Plan Act of 1975, provides for the licensure and regulation of health care service plans by the Department of Managed Health Care and makes a willful violation of the act a crime. Existing law also provides for the regulation of health insurers by the Department of Insurance. Existing law authorizes health care service plans and health insurers that cover prescription drugs to utilize reasonable medical management practices, including prior authorization and step therapy, consistent with applicable law. This bill would prohibit a medical service plan and a health insurer from subjecting a naloxone product or another opioid antagonist approved by the United States Food and Drug Administration, or a buprenorphine product or long-acting injectable naltrexone for detoxification or maintenance treatment of a substance use disorder, to prior authorization or step therapy. Because a willful violation of these provisions by a health care service plan would be a crime, this bill would impose a state-mandated local program. The California Constitution requires the state to reimburse local agencies and school districts for certain costs mandated by the state. Statutory provisions establish procedures for making that reimbursement. This bill would provide that no reimbursement is required by this act for a specified reason.