FDA drug adverse events

Top reported adverse reactions for a drug from the FDA FAERS database (openFDA), ranked by report count - a fast read on a drug's real-world safety signal. Send GET /api/drug-adverse-events with the required field drug and pay $0.001 per call over x402 or MPP (there is no free tier). It returns a JSON object with drug, count, topReactions and source.

Live FDA data, no key. ?drug=aspirin&limit=10

Category: Live public data · Tags: fda drug adverse-events faers openfda health government

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Parameters

Example request

curl -i "https://agent402.tools/api/drug-adverse-events?drug=aspirin&limit=10"

Without payment this returns HTTP 402 Payment Required with the exact price for drug-adverse-events; any x402 v2 or MPP client pays it and retries.

Example response

{
  "drug": "aspirin",
  "count": 2,
  "topReactions": [
    {
      "reaction": "NAUSEA",
      "reports": 4211
    },
    {
      "reaction": "DYSPNOEA",
      "reports": 3987
    }
  ],
  "source": "api.fda.gov (openFDA FAERS, public domain)"
}

From an MCP client

catalog.call {
  "slug": "drug-adverse-events",
  "params": {
    "drug": "aspirin",
    "limit": 10
  }
}

The hosted connector at https://agent402.tools/mcp needs a payment for drug-adverse-events; the stdio package pays it from a wallet or from AGENT402_CREDITS_KEY. Local install: npx -y agent402-mcp.

Errors and behavior

• drug is required. An input the tool rejects returns an HTTP 4xx whose body carries error, tool, expected, required and example, so the caller can correct it.
• A paid call that ends in any status of 400 or above is not charged over x402, MPP or a prepaid credits key: settlement is cancelled when the tool fails. The exception is a Tempo push credential, a transfer the buyer sent before the call: it settles before the tool runs, so if the tool then fails the payment is recorded as a refund owed to the paying wallet.
• Wallet-only: this tool reaches the network or stored state, so it has no proof-of-work tier. A prepaid card-credits key issued earlier (Authorization: Bearer a402_...) also pays it.
• A POST with a JSON body to /api/drug-adverse-events is served as this GET, with the body as the input.
• An Idempotency-Key header makes a retried paid call replay the first 200 instead of charging again (an answer larger than 1 MB is not replayed).

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
client.setSpendControls?.(false); // keep your own spending ceiling in code
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/drug-adverse-events?drug=aspirin&limit=10");

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