# RxNorm Drug Lookup API

> RxNorm Drug Lookup API is a paid API for AI agents from 2s.io, paid per call via x402, $0.0012/call, status unknown (last checked 2026-09-16).

Search for drug names or retrieve canonical RxNorm concept details and related concepts by RxCUI from the NIH National Library of Medicine RxNorm database

## Facts

- Endpoint: GET https://2s.io/api/medical/rxnorm
- Price: $0.0012/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/rxnorm-drug-lookup-api-835e4905
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_GrESw7LDP2Rth_cq1jlXJ

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability rxnorm-drug-lookup-api-835e4905
```

Example prompt: Look up 'metformin' in RxNorm and give me the top 3 matching drug concepts with their RxCUI codes.

## When to prefer this

Use this endpoint when you need to resolve drug names (brand or generic) to standardized RxNorm identifiers, or when you need canonical drug concept details and related concepts given a known RxCUI. Ideal for normalizing medication names in clinical workflows, enriching drug data pipelines, or verifying pharmaceutical terminology against the authoritative US government drug database.

## Known failure modes

- No results found for an obscure or misspelled drug name — returns empty items array
- Both 'term' and 'rxcui' provided simultaneously — only one should be used (XOR)
- Neither 'term' nor 'rxcui' provided — missing required query parameter
- Invalid rxcui value — may return empty or error response
- Limit parameter out of range (must be 1–20) — validation error

## How this service works

Normalize and verify drug names against RxNorm, the canonical US drug vocabulary from the NIH. Two modes: term ("tylenol 500mg", brand or generic, typos tolerated) returns ranked RxCUI candidates with normalized names and match scores; rxcui returns the canonical concept (name, term type like IN=ingredient / SBD=branded drug / SCD=clinical drug, suppression flag) plus related concepts — active ingredients, brand names, and available dose forms. Use before writing prescriptions data, drug interactions queries, or pharmacy integrations: verify the drug exists and get its stable identifier instead of trusting model memory. Sibling: /api/medical/icd10 (diagnosis codes). Public-domain NIH data.

## Output

Returns a JSON object with an 'items' array of matched drug concepts, each containing the drug name, RxCUI identifier, rank, and relevance score. In RxCUI detail mode, also returns related concepts and canonical concept metadata. Source attribution to NIH NLM RxNorm is included.

## Example request

```json
{
 "input": {
  "type": "http",
  "method": "GET",
  "queryParams": {
   "term": "aspirin",
   "limit": 5
  }
 }
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "queryParams"
   ],
   "properties": {
    "type": {
     "const": "http"
    },
    "method": {
     "const": "GET"
    },
    "queryParams": {
     "properties": {
      "term": {
       "type": "string",
       "description": "Free-text drug name, brand or generic (XOR with rxcui)."
      },
      "limit": {
       "type": "integer",
       "default": 5,
       "maximum": 20,
       "minimum": 1,
       "description": "Max candidates (term mode)."
      },
      "rxcui": {
       "type": "string",
       "description": "RxNorm concept id for canonical detail + related concepts (XOR with term)."
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/rxnorm-drug-lookup-api-835e4905/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 2s.io](https://www.zero.xyz/host/2s.io/llms.txt)