RxNorm Overview

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RxNorm Overview

• October 2005
• John Kilbourne MD
• National Library of Medicine
• kilbourj_at_mail.nih.nlm.gov

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A brief look at RxNorm

• The motivations to create RxNorm
• The scope and content of RxNorm
• The semantic model of RxNorm

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Motivations to create RxNorm
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Motivation (1)

• Unable to easily detect synonymy in the UMLS
  Metathesaurus
• Metathesaurus
• set of equivalence classes of synonymous terms
  maintained by the NLM
• those terms that mean the same thing are assigned
  the same Concept Unique Identifier

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Are these the same or different?

• Ciprofloxacin 100mg/50mL IV Infusion
• Ciprofloxacin 400mg/200mL IV Infusion
• Ciprofloxacin Lactate 0.2 in Saline
• Ciprofloxacin IV Soln 2 MG/ML

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Motivation (2)

• Need for data sharing across different drug
  information vendors
• RxNorm relates the terms and codes from various
  vendors, permitting interoperability
• RxNorm indicates when names from different
  sources are synonymous, and gives them the same
  RxNorm identifier (RxCUI)

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Motivation (3)

• Provide a set of clinically useful and
  normalized names for orderable drugs
• An end-user interface could use these names for
  instance
• Not perfectly realized at this time

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Scope and content of RxNorm
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RxNorm as a set of concepts

• A single concept can have multiple names and
  derive from multiple sources it receives a
  single RxCUI (identifier)
• The names in a single concept mean (essentially)
  the same thing
• RxCUI 392151
• AMOXICILLIN 200 MG ORAL TABLET
• Amoxicillin 200 MG Oral Tablet
• Amoxicillin trihydrate 200mg tablet
• Amoxicillin trihydrate 200mg tablet (product)

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Current source vocabularies in RxNorm (October
2005)

• MDDB (Medispan)
• MMSL (Multum)
• MMX (MicroMedex)
• MTHFDA (FDA website files)
• NDDF (First DataBank)
• RXNORM
• SNOMEDCT (SNOMED CT)
• VANDF (VA terminology)

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Clinical drugs

• RxNorm is a standardized nomenclature of clinical
  drugs (and their components)
• Clinical drug
• Pharmaceutical product given to (or taken by) a
  patient with a therapeutic or diagnostic intent
• Meant to represent the clinicians intent

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Normalized names

• Name of a clinical drug combines its
  ingredient(s), strength(s), form, and brand name
  if present
• Acetaminophen 500 MG Oral Tablet
• Acetaminophen 500 MG Oral Tablet Tylenol
• Oral liquid strengths are normalized to represent
  strength per 1 mL

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Normalized liquid strengths

• AMOXICILLIN TRIHYDRATE 50MG/5ML SUSP
• Amoxicillin 10 MG/ML Oral Suspension
• AMOXICILLIN TRIHYDRATE 50MG/5ML SUSP
• AMOXICILLIN TRIHYDRATE 50 MG/5ML ORAL POWDER

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Scope of dose form in RxNorm

• Physical form in which the drug is (specified to
  be) administered
• No reference to pack size, the form in which it
  was manufactured, the form it takes when it
  arrives at the dispensary
• Prescribers point of view is represented, not
  the pharmacists

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Also explicitly out of scope

• Structural classes (Penicillins)
• Therapeutic uses (Antipsychotics)
• Functional classes (Vasodilators)
• Anything other than ingredients, dose forms, and
  strengths

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Semantic model of RxNorm
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Meanings of the concepts

• Semantic model refers to the structures and
  links that permit a user to understand what a
  concept really means
• TermTypes
• Relationships
• Attributes

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Components of the model
13 TermTypes
8 Relationship pairs
SCD, SBD SCDC, SBDC SCDF, SBDF IN, BN DF (SY,
OBD, OCD, ET)
constitutes / consists_of contains /
contained_in dose_form_of / has_dose_form form_of
/ has_form ingredient_of / has_ingredient tradena
me_of / has_tradename precise_ingredient_of /
has_precise_ingredient contains / contained_in
(not currently used)
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SCD

• Semantic clinical drug
• Ingredient or ingredients
• Dose form as given to a patient
• Numerical strength
• 3 significant digits
• Units
• Controlled list
• Normalized to each or per single unit

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SCD examples

• Amoxicillin 250 MG Oral Capsule
• Hydrogen Peroxide 30 MG/ML Topical Solution

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SBD

• Semantic branded drug
• ltSCDgt Brand name
• Amoxicillin 250 MG Oral Capsule Amoxil
• Amoxicillin 40 MG/ML Oral Suspension Dispermox

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SCDC

• Semantic clinical drug component
• Ingredient
• Numerical strength
• Units
• Amoxicillin 250 MG
• Acetaminophen 32 MG/ML

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SBDC

• Semantic branded drug component
• Ingredient
• Numerical strength
• Units
• Brand name
• Clonazepam 1 MG Klonopin Wafer
• Nifedipine 30 MG Procardia
• Estradiol 0.00104 MG/HR Alora

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SCDC

• Semantic clinical drug component
• Ingredient
• Numerical strength
• Units
• Acetaminophen 25 MG/ML
• Acyclovir 200 MG

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IN

• Ingredient
• Active ingredient
• Precise vs base (salts distinguished using
  precise_ingredient_of relationship)
• Mitomycin
• Amikacin

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SCDF

• Semantic clinical drug form
• Ingredient
• Dose form
• Amoxicillin Oral Tablet
• Potassium Chloride Injectable Solution
• Coal Tar / Salicylic Acid Topical Cream

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SBDF

• Semantic branded drug form
• Branded ingredient
• Dose form
• Amoxicillin Oral Suspension Biomox
• Isosorbide Mononitrate Oral Tablet Isordil

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DF

• Dose form
• as administered to the patient
• Oral Solution
• Capsule

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(No Transcript)
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Relationships
constitutes / consists_of
tradename_of / has_tradename
SCDlt-gtSCDC SBDlt-gtSBDC,SCDC
BNlt-gtIN SBDClt-gtSCDC SBDlt-gtSCD SBDFlt-gtSCDF
dose_form_of / has_dose_form
DFlt-gt SCD,SCDF,SBD,SBDF
form_of / has_form
INlt-gtIN
ingredient_of / has_ingredient
INlt-gtSCDC,SCDF BNlt-gtSBDC,SBD,SBDF
contains / contained_in
SCDlt-gtDrug delivery device
isa / inverse_isa
precise_ingredient_of / has_precise_ingredient
SCDlt-gtSCDF SBDlt-gtSBDF
SCDlt-gtIN (precise ingredient)
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Lattice diagram (of vertical relationships)
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RxNorm attributes

• UMLSCUI, UMLSAUI link to the UMLS Metathesaurus
• this allows access to SNOMED,VANDF, and MeSH drug
  classes
• RxNorm is not meant to replace commercial drug
  vocabularies
• NDC coverage, for instance is incomplete at
  present

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Thank you!
http//www.nlm.nih.gov/research/umls/rxnorm/index.
html http//www.nlm.nih.gov/research/umls/rxnorm_d
oco.html