FHIRfly
Dashboard

RxClass Search API

Search drug classification hierarchies from NLM MED-RT.

Endpoint

GET /v1/rxclass/search

Quick Start

Node.js
import { Fhirfly } from "@fhirfly-io/terminology";

const client = new Fhirfly({ apiKey: "YOUR_API_KEY" });

// Search for drug classes related to blood pressure
const results = await client.rxclass.search({
  q: "angiotensin"
});

console.log(`Found ${results.total} classes`);
for (const item of results.items) {
  console.log(`${item.class_id}: ${item.class_name} (${item.class_type})`);
}

Parameters

Text Search

Parameter Description Example
q General text search q=angiotensin

Filters

Parameter Type Description Example
class_type string Classification type MoA, PE, EPC, TC, SC, PK

Pagination & Response

Parameter Default Max Description
limit 20 100 Results per page
page 1 100 Page number
shape compact — compact, standard, full
sort relevance — relevance, class_name

Example Response

{
  "facets": {
    "class_type": {
      "EPC": 12,
      "MoA": 8,
      "PE": 5,
      "TC": 3
    }
  },
  "has_more": false,
  "items": [
    {
      "class_id": "N0000175355",
      "class_name": "Angiotensin 2 Receptor Blocker",
      "class_type": "EPC"
    },
    {
      "class_id": "N0000000186",
      "class_name": "Angiotensin-converting Enzyme Inhibition",
      "class_type": "MoA"
    }
  ],
  "limit": 20,
  "meta": {
    "legal": {
      "attribution_required": false,
      "citation": "NLM MED-RT via RxClass. Accessed 2026-03-01 via FHIRfly.",
      "license": "UMLS",
      "source_name": "RxClass"
    }
  },
  "page": 1,
  "total": 28,
  "total_capped": false
}

Use Cases

Find Mechanisms of Action

Node.js
const results = await client.rxclass.search({
  q: "inhibitor",
  class_type: "MoA"
});

Find FDA Pharmacologic Classes

Node.js
const results = await client.rxclass.search({
  class_type: "EPC"
});

Search Physiologic Effects

Node.js
const results = await client.rxclass.search({
  q: "platelet",
  class_type: "PE"
});

Find Therapeutic Categories

Node.js
const results = await client.rxclass.search({
  q: "antihypertensive",
  class_type: "TC"
});

Facets

RxClass search returns these facets:

Facet Description
class_type Distribution by classification type (MoA, PE, EPC, TC, SC, PK)

Valid Values

Class Type Values

  • MoA — Mechanism of Action (how the drug works)
  • PE — Physiologic Effect (the drug's effect on body processes)
  • EPC — Established Pharmacologic Class (FDA-designated)
  • TC — Therapeutic Category (VA therapeutic use)
  • SC — Structural Class (chemical structure)
  • PK — Pharmacokinetics (absorption, distribution, metabolism)

Required Scope

rxclass.search

See Also