# FDA Adverse Event Counts

> FDA Adverse Event Counts is a paid API for AI agents from fda-drugs.use.x402atlas.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-31).

Returns FAERS adverse event report counts for a drug, including total reports, serious report counts, and the most frequently reported reactions with their shares.

## Facts

- Endpoint: GET https://fda-drugs.use.x402atlas.com/adverse-events?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fda-adverse-event-counts-5a38b57f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FDWSemFPMFyQ-MwESno5X

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 fda-adverse-event-counts-5a38b57f
```

Example prompt: Pull the FDA adverse event counts for metformin from FAERS — I want to see the total reports, how many were serious, and the top 20 most reported reactions with their counts and shares.

## When to prefer this

Use this endpoint when you need quantitative pharmacovigilance signals from the FDA's FAERS database — specifically report counts, serious event rates, and ranked reaction profiles for a named drug. Prefer it over FDA label lookups when you need post-market safety signal data rather than prescribing information, and over recall endpoints when you need reaction frequency data rather than enforcement actions. Best suited for drug safety research, regulatory monitoring, and pharmacovigilance workflows — not for clinical decision support.

## Known failure modes

- Drug name not found in FAERS returns a response with a note field and zero/empty counts
- Invalid drug name format (violating pattern) returns a validation error
- Limit parameter out of range (below 1 or above 100) returns a validation error
- FAERS data temporarily unavailable returns a service error
- Misspelled drug name may return no data or data for a different substance

## How this service works

FDA adverse event counts — FAERS reports naming a drug: total reports, how many were serious, and the most reported reactions with counts and shares. Report counts are not incidence and prove no causation; use for pharmacovigilance signals and safety research, not clinical decisions.

## Output

A JSON object containing the drug name as searched, retrieval timestamp, FAERS data-through date, total report count, serious report count, serious share (ratio), a fixed caveat note about interpretation, source attribution, and an array of the most-reported reactions ranked by frequency — each with MedDRA preferred term, report count, and share of total reports.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "drug"
     ],
     "properties": {
      "drug": {
       "type": "string",
       "pattern": "^[A-Za-z0-9][A-Za-z0-9 .,'()/-]{0,99}$",
       "description": "Brand or generic name; omitted runs the example"
      },
      "limit": {
       "type": "integer",
       "default": 20,
       "maximum": 100,
       "minimum": 1,
       "description": "Reaction terms to return"
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "as_of",
      "source",
      "caveat",
      "modified",
      "drug",
      "total_reports",
      "serious_reports",
      "serious_share",
      "reactions",
      "data_through"
     ],
     "properties": {
      "drug": {
       "type": "string",
       "description": "Name as searched"
      },
      "note": {
       "type": "string",
       "description": "Present only when no report names the drug"
      },
      "as_of": {
       "type": "string",
       "format": "date-time",
       "description": "Retrieval time, UTC"
      },
      "caveat": {
       "type": "string",
       "description": "Fixed interpretation note"
      },
      "source": {
       "type": "object",
       "required": [
        "name",
        "url",
        "citation"
       ],
       "properties": {
        "url": {
         "type": "string"
        },
        "name": {
         "type": "string"
        },
        "citation": {
         "type": "string",
         "description": "Credit line FDA asks for"
        }
       },
       "additionalProperties": false
      },
      "modified": {
       "type": "boolean",
       "description": "Always true: fields are normalized, not the agency's verbatim record"
      },
      "reactions": {
       "type": "array",
       "items": {
        "type": "object",
        "required": [
         "term",
         "count",
         "share"
    
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fda-adverse-event-counts-5a38b57f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fda-drugs.use.x402atlas.com](https://www.zero.xyz/host/fda-drugs.use.x402atlas.com/llms.txt)