# Mortar — Drug Interaction API — for AI agents and LLMs

> Educational drug-drug interaction lookup and a drop-in replacement for the
> discontinued NLM RxNav interaction API. Send a list of drug names; get pairwise
> interactions in the NLM-mirrored shape, with severity, description, and source.
> RxNorm normalization handles brand names and typos. Informational only — NOT
> clinical decision support, NOT a safe/unsafe verdict. Distributed via RapidAPI.

## Authentication
Sold on RapidAPI. Subscribe to a plan, then call through the RapidAPI gateway:
  X-RapidAPI-Key: <your-rapidapi-key>
  X-RapidAPI-Host: <your-rapidapi-host>
RapidAPI authenticates, meters, and proxies the request. No separate API keys.

## Base URL
https://mortar.rgtz.dev   (or your RapidAPI host)

## Endpoints
- POST /interactions  — Pairwise interactions for a list of drug names.
- GET  /v1/manifest   — Machine-readable capabilities (no auth).
- GET  /openapi.yaml  — OpenAPI 3.0 spec (no auth).
- GET  /health        — Health check (no auth).

## Request
POST /interactions
{
  "drugs": ["warfarin", "aspirin", "simvastatin"],   // 2-50 names, generic or brand
  "explain": false                                    // optional plain-language explanations
}

## Response (NLM-mirrored, trimmed)
{
  "disclaimer": "Educational, informational drug-interaction data only ...",
  "resolved": [ { "input": "warfarin", "found": true, "rxcui": "11289", "name": "warfarin", "tty": "IN", "match": "exact" } ],
  "unresolved": [],
  "fullInteractionTypeGroup": [
    {
      "sourceName": "ONCHigh",
      "fullInteractionType": [
        {
          "minConcept": [ { "rxcui": "11289", "name": "warfarin", "tty": "IN" }, { "rxcui": "1191", "name": "aspirin", "tty": "IN" } ],
          "interactionPair": [
            {
              "interactionConcept": [ { "minConceptItem": {...}, "sourceConceptItem": {...} }, {...} ],
              "severity": "high",
              "description": "Anticoagulants combined with antiplatelet agents increase the risk of serious bleeding."
            }
          ]
        }
      ]
    }
  ]
}

## Notes
- severity is "high" (ONCHigh) or "N/A" (openFDA labels carry no severity).
- With explain:true each interactionPair gains an "explanation" string.
- Names that cannot be resolved appear in "unresolved"; the request still succeeds.
- Data: public ONCHigh DDI list + openFDA labeling, normalized via NLM RxNorm. No DrugBank/DDInter.

## Errors
Envelope: { "error": { "code", "message", "hint", "request_id" } }
Codes: forbidden, invalid_request, upstream_failed, internal_error