In the midst of national concern over the opioid epidemic and the large number of prescription opioid overdose deaths in the United States, federal and state officials are paying greater attention to the manner in which opioids are prescribed. Prescription opioid-related overdose deaths dramatically increased from 1999 to 2010 in the United States in conjunction with increased opioid prescribing, and overdose deaths involving prescription opioids were five times higher in 2016 than in 1999. Over the last year, the Trump Administration, Congress, state governments, and the private sector have all taken action to address prescription drug abuse. Initiatives range from state and private health care initiatives, such as limiting the number of pills in a prescription, to major legislation, such as the Comprehensive Addiction and Recovery Act (CARA; P.L. 114-198 ), which included many provisions to address prescription drug abuse. In 2016, an estimated 11.8 million individuals aged 12 or older (4.4% of this population) misused opioids in the past year, including 11.5 million pain reliever misusers and 948,000 heroin users. Prescription painkillers—natural and semisynthetic opioids (e.g., oxycodone, hydrocodone, and morphine) are involved in more overdose deaths than any other opioid. Of the individuals who used prescription painkillers non-medically in 2016, more than half (53.0%) received the drugs from a friend or relative either for free, by purchase, or by stealing. Aside from prescription painkillers such as oxycodone, other commonly abused prescription medications include benzodiazepines and amphetamine-like drugs. Some academic and government experts link the crackdown on prescription drug abuse and the comparatively higher cost of prescription pain relievers on the black market to the uptick in heroin abuse. The number of individuals aged 12 or older currently using heroin (475,000 in 2016) has nearly tripled since 2002. Like many prescription pain relievers, heroin is an opioid. Unlike prescription pain relievers, however, heroin is a Schedule I controlled substance under the Controlled Substances Act and has no accepted medical use in the United States. Most prescription drugs that are misused are originally prescribed by a physician (rather than, for example, being stolen from pharmacies); therefore, attention has been directed toward preventing the diversion of prescription drugs after the prescriptions are dispensed. Prescription drug monitoring programs (PDMPs) maintain statewide electronic databases of dispensed prescriptions for controlled substances. PDMP information can aid medical professionals and those in law enforcement in identifying patterns of prescribing, dispensing, or receiving controlled substances that may indicate abuse. For over a decade, the federal government has provided financial support for state-level PDMPs. In 2002, Congress established the Harold Rogers PDMP grant, administered by the Department of Justice (DOJ), to help law enforcement, regulatory entities, and public health officials analyze data on prescriptions for controlled substances. Three years later, Congress and the President enacted the National All Schedules Prescription Electronic Reporting Act of 2005 (NASPER) requiring the Secretary of Health and Human Services (HHS) to award grants to states to establish or improve PDMPs. In 2016, CARA authorized PDMP activity under two grant programs administered by DOJ and HHS. Congress has demonstrated a particular interest in facilitating interoperability among state-level PDMPs, as well as in establishing national programs. Policymakers have focused on enhancing state-level databases and interstate information sharing, and some have suggested establishing a national system. Related issues that policymakers may consider are whether PDMPs and their interstate information-sharing platforms adequately protect personally identifiable and related health information, and whether they can ensure that patients with legitimate medical needs have access to prescriptions. Congress may also exercise oversight with respect to the role of PDMPs in the Administration's efforts to combat the prescription drug epidemic; policymakers may assess the extent to which the relevant departments and agencies have taken steps to accomplish these PDMP-related goals. This report provides an overview of PDMPs, including their operation, enforcement mechanisms, costs, and financing. It also examines the effectiveness of PDMPs and outlines federal grants supporting PDMPs. Finally, this report discusses relevant considerations for policymakers including interstate data sharing, interoperability, protection of health information, and the possible link between the crackdown on prescription drug abuse and rise in heroin abuse. PDMPs maintain statewide electronic databases of designated information on specified prescription drugs dispensed within the states. Data are made available to individuals or organizations as authorized under state law; these may include prescribers, law enforcement officials, licensing boards, or others. Possible uses of PDMPs include identifying or preventing drug abuse and diversion; facilitating the identification of prescription drug-addicted individuals and appropriate intervention and treatment; outlining use and abuse trends to inform public health initiatives; and educating individuals about prescription drug use, abuse, and diversion. In addition to uses of PDMPs aimed at drug abuse and diversion, an explicit goal of PDMPs is supporting access to controlled substances for legitimate medical use. This may best be understood by viewing PDMPs in comparison to earlier, paper-based programs called multiple-copy prescription programs. For example, in 1914 a New York state law required physicians to use state-issued, serialized, duplicate prescription forms for certain drugs. Similarly, California began a multiple-copy prescription program using triplicate forms for specified narcotics in 1939; it expanded to monitor all schedule II narcotics in 1972 and schedule II non-narcotics in 1981. Studies of multiple-copy prescription programs found that many prescribers did not order the required prescription forms, rendering them unable to prescribe specified controlled substances even when medically appropriate. In addition, the ability to check a patient's prescription history using an electronic PDMP might give prescribers more confidence when considering the use of drugs with high risk of abuse and prevent the prescribing of contraindicated medications. As of February 2018, 50 states, the District of Columbia, and two territories (Guam and Puerto Rico) had operational PDMPs within their borders. The entity responsible for administering the PDMP varies by state and may be a pharmacy board, department of health, professional licensing agency, law enforcement agency, substance abuse agency, or consumer protection agency. Of the authorized state PDMPs (including the District of Columbia), most (40) are administered by either pharmacy boards or health departments. State laws determine which schedules of controlled substances are monitored under each program (see text box for a brief explanation of schedules), what information is to be submitted, the means by which dispensers or dispensaries submit the required information, and the time frame in which information must be submitted. Each state also determines which entities dispensing prescriptions for controlled substances are required to submit data to the PDMP. Most states require retail pharmacies and dispensing practitioners (e.g., physicians and/or veterinarians) to submit data to the PDMP. Some states also have statutory authority to require out-of-state, mail order, and Internet pharmacies to submit data to the PDMP regarding prescription or controlled drugs dispensed to residents of the state. For instance, if a patient in Alabama receives a prescription for a monitored drug from an out-of-state mail order pharmacy, the mail order pharmacy must report the prescription to the Alabama PDMP. Of note, information on medications (e.g., methadone or buprenorphine) dispensed at federally assisted drug treatment programs generally may not be reported to PDMPs without patient consent under federal privacy regulations (42 C.F.R. Part 2). These regulations place strict limitations on the disclosure, and redisclosure, of patient information created and maintained by such programs that identifies the individual patient as a drug abuser, or links the individual to the program. Access to information contained in the PDMP database is determined by state law and varies by state. The majority of states allow pharmacists and practitioners to access information related to their patients, and some also allow other entities—law enforcement, licensing and regulatory boards, state Medicaid Programs, state medical examiners, and research organizations—to access the information under certain circumstances. State laws outline the procedures by which information from the PDMP may be accessed. With respect to how the states identify and investigate cases of potential prescription drug diversion or abuse, PDMPs may be classified as reactive or proactive . In essence, "[s]tates with [r]eactive PDMPs ... generate solicited reports only in response to a specific inquiry made by a prescriber, dispenser, or other party with appropriate authority" while "[s]tates with [p]roactive PDMPs ... identify and investigate cases, generating unsolicited reports whenever suspicious behavior is detected." State PDMPs vary widely with respect to whether or how information contained in the database is shared with other states. While some states do not have measures in place allowing interstate sharing of information, others have specific policies that govern sharing of information across state lines. These policies may be based on factors such as agreed-upon reciprocity between states, or whether a request stems from an ongoing investigation. As of September 20, 2017, 43 states were engaged in interstate data sharing while 5 states were still implementing interstate data sharing. Researchers provided states with guidance in creating memoranda of understanding (MOUs) for interstate data exchange. Questions that states may consider when drafting an MOU include the following: How is the information to be reported? How will the information be used by the relevant states? What are the guidelines on data retention? What are the state responsibilities in the event of a data breach? Are there measures in place for conflict resolution? What are the consequences of potential data misuse?