The Ambulatory Care Drug Database System
- Ambulatory and Hospital Care Statistics Branch
National Center for Health Statistics
3311 Toledo Road
Hyattsville, MD 20782
- (301) 458-4600
- Beginning with the 2006 survey year, every drug reported in the National Ambulatory Medical Care Survey and National Hospital Medical Care Survey is assigned characteristics, during data processing, based on the Lexicon Plus®, a proprietary database of Cerner Multum, Inc. (The previous Ambulatory Care Drug Database, used prior to the 2006 survey year data, was based on the Food and Drug Administration's National Drug Code Directory). The Lexicon Plus is a comprehensive database of all prescription and some nonprescription drugs products available in the U.S. drug market. Drugs reported in NAMCS and NHAMCS are coded twice: first "as entered" on the survey data collection form, using an NCHS-assigned 5-digit code, and second using a corresponding 6-digit generic-equivalent code based on the Multum classification. The Multum code for a given drug reflects up to 6 of its components. Therapeutic class (drug category) is also assigned using Multum; up to 4 therapeutic classes can be assigned per drug in NAMCS and NHAMCS.
- The Ambulatory Care Drug Database (ACDD) was updated to reflect drugs in the database as of the 2015 survey year. It is important to note that the drug database as well as the Multum classification can change over time. For the database, this can occur when a drug that was not previously assigned a code by the Multum classification is added to that classification and its DRUGID value in the ACDD is then changed to reflect the new Multum designation. Also, Multum can change its therapeutic category classification. For example, a drug that was assigned to only a second-level therapeutic category in one year may now be assigned to a new third-level category. The ACDD continues to undergo general housekeeping to remove duplicate listings, correct misspellings, etc. Results from searches in the current version of the database will reflect the information used to process the current year of survey data. If a data user is looking for drugs over time, it is important to also check that drug’s identifying information as well as Multum’s therapeutic category structure in the public use file documentation for the earlier years, in order to ensure that the correct codes are being selected.
- Note that the National Center for Health Statistics has not released any NHAMCS outpatient data since 2011. Drugs that were found in the 2015 NAMCS and 2015 NHAMCS Emergency Department public use files will show up with an estimate in the search results. Drugs showing up without an estimate are in the database but did not occur in the 2015 data.
- Please note that the primary purpose of this system is to facilitate the identification of drug codes used in NAMCS and NHAMCS by data users. These codes can then be used in the analysis of survey data. The query system is NOT intended to provide quick estimates of drug utilization because drugs can appear on the database in different ways, and, unless one takes this into account, estimates may be based on incomplete information. Furthermore, estimates shown may not be statistically reliable. They are presented to help researchers assess the relative frequency of the drug’s occurrence when deciding about the feasibility of studying it and to help data users verify that they are getting correct results when running the data themselves. More information on the purpose and use of the Ambulatory Care Drug Database is available here.
- Fill out the form below to search the database for a list of drugs matching your search criteria. See Guidance on Search Criteria for more information.
- Use pound (#) for a single unknown character or an asterisk (*) for a group of unknown characters.
NOTE: The Ambulatory Care Drug Database made the switch to a Multum-based system of drug classification with the 2006 data year. As we work more with this system, we are identifying some issues which may affect data users. Specifically, in developing the new online drug database application, we discovered that Multum assigns certain drug characteristics differently than NCHS had done in the past. This was first noticed with aspirin, which Multum classifies as a prescription drug. The reason for this appears to be that there are certain strengths of aspirin that are only available by prescription, and Multum appears to code up to the highest level rather than differentiating prescription and non-prescription forms of drugs. This was also noticed with the DEA Status variable. Some drugs, such as codeine, may have multiple DEA statuses, depending on their dosage and route of administration. Multum codes such drugs up to their highest DEA status. Beginning with the 2008 drug data, we have worked with Multum to reclassify drugs within our own database to reflect multiple statuses. We wish to bring such issues to the attention of our data users so that they can be aware of any seeming contradictions with regard to these characteristics.
Drug Entry Code: A unique, NCHS-assigned 5-digit code, applied to each drug reported in the NAMCS and NHAMCS.
Drug Entry Name: The specific drug identifier entered by the survey respondent. It corresponds with the entry made in the medical record, prescription, or medical order, and may be a trade/brand/proprietary or generic name. It should not be a drug class, although sometimes respondents will enter specific therapeutic effects, like allergy relief or antidepressant, in lieu of names, and these will also receive codes.
Generic-Equivalent Code: A 6-digit code based on the Multum classification. If a match could not be found within Multum, NCHS developed its own code. These codes, unlike NCHS generic codes prior to 2006, can encompass up to 6 ingredients for each drug. Multum codes begin with the letter "d", and NCHS codes begin with the letters "a", "c" or "n". The generic-equivalent code is the same as the ingredient code for single-ingredient products, but not for combination products. See "Ingredient Code" below for more information. Information about Multum is also available in the NAMCS and NHAMCS Public Use Data File Documentation.
Generic-Equivalent Name: This is a listing of ingredient names (up to 6) comprising the component(s) of a given drug.
Ingredient Code: A 6-digit code based on the Multum classification, used to identify the active ingredients of drugs. A maximum of 6 ingredients can be identified for each drug in the NAMCS and NHAMCS. Note that the ingredient code and the generic-equivalent code will be the same for single-ingredient products, but not for combination products. For example, the antibiotic drug Augmentin is "generically equivalent" to the Multum code for amoxicillin-clavulanate (d00089). But those ingredients also have their own unique codes in the Multum classification (amoxicillin, d00088 and clavulanate, d04405).
Ingredient Name: The names of the active ingredients used in drugs.
Therapeutic Class (Multum's "Drug Category"): Beginning with the 2006 data year, therapeutic class is being assigned using Multum's drug categories. (Prior to this time, the National Drug Code Directory was used to assign therapeutic class.). The Multum Lexicon provides a 3-level nested category system that assigns a therapeutic class to each drug and each ingredient of the drug (e.g., for naproxen: the broadest category is central nervous system agents [level 1]; the more detailed category is analgesics [level 2]; and the most detailed category is nonsteroidal anti-inflammatory agents [level 3]). Not all drugs have three classification levels; some may only have two [e.g. for digoxin: cardiovascular agents [level 1]; inotropic agents [level 2]), others only have one. Each drug may have up to four therapeutic categories in the ambulatory care drug database. Note that Multum uses a “combination” category for some multiple ingredient drugs. These include antihypertensive combinations, antiasthmatic combinations, upper respiratory combinations, psychotherapeutic combinations, bronchodilator combinations, sex hormone combinations, skeletal muscle relaxant combinations, and narcotic analgesic combinations. This categorization may be sufficient for certain analyses but not for others because it lacks information about the therapeutic effect of the individual ingredients that make up the combination. For example, the drug HYDROCHLOROTHIAZIDE; LOSARTAN is identified as an antihypertensive combination. Therefore, we know that this drug has an antihypertensive drug effect. However, based on this combination category we do not know that the drug’s single ingredients have the therapeutic effects of a diuretic and angiotensin II inhibitor, which is relevant for some analyses. As a result, NCHS decided that, in addition to assigning therapeutic categories to each drug, a separate file would be provided that could be merged with the public use file, and that listed up to 6 ingredients for each drug along with up to 3 therapeutic categories for each ingredient.
Prescription Status: A code designed to identify the federal legal status (prescription or nonprescription) of the drug entered.
Composition Status: A code used to distinguish between drug products made up of a single ingredient versus a fixed active ingredient combination. Fixed active ingredient combination drug products are referred to as a combination drugs in NAMCS and NHAMCS.
DEA Status: Controlled medications, because of their significant potential for dependence or abuse and their possible diversion into illicit channels, are regulated under Federal law by the Department of Justice, Drug Enforcement Agency (DEA). The Controlled Substance Act of 1970 identifies each controlled drug as one of five schedules. Schedule I drugs, like heroin and LSD, have a higher potential for abuse and no current accepted medical usefulness for treatment in the United States. Each successive schedule, II through V, reflects a decreasing degree of dependence and potential for abuse.
The Drug Search Results screen displays search results by drug entry code, drug entry name, generic-equivalent name, and number of drug mentions (defined below) for the most recent year of data. Note that, for 2015, the data only include physician office visits from NAMCS and hospital emergency department visits from NHAMCS, because hospital outpatient department data have not yet been released. If number of mentions is blank, there were no recorded entries for the drug that year. By clicking on any of the underlined text in the Drug Search Results, information will be displayed on the drug's characteristics, number of mentions, and mention rate.
Drug Mention: The estimate of drug mentions for each drug reported in the most recently available NAMCS and NHAMCS datasets is provided. For 2015, in addition to NAMCS, only NHAMCS emergency department data have been released to date; hospital outpatient data are not included in the drug mention estimates. A drug mention is the physician’s entry on the survey collection form of a pharmaceutical agent--by any route of administration--for prevention, diagnosis, or treatment. Generic as well as brand-name drugs are included, as are nonprescription and prescription drugs. Along with all new drugs, the physician also records continued medications if the patient was specifically instructed or expected to continue the medication. For 2015, as many as 30 drugs can be reported per ambulatory care visit. If no figure is displayed, there were no mentions of that drug in the current year of data. Figures are presented as one would generate them from public use data and can be used to make sure one’s analysis is yielding the correct result. The figures shown here do not include standard errors and may not be statistically reliable. They are presented only to show the relative frequency of their occurrence in the current year of data.
Drug Mention Rate: The drug mention rate is the number of mentions for a particular drug code per 10,000 ambulatory medical care visits based on the most recent year of data. For 2015, this includes physician office visits from NAMCS and hospital emergency department visits from NHAMCS only, since hospital outpatient department data have not been released to date. If a number of mentions is displayed without a mention rate, the mention rate was less than 1 per 10,000 visits.