`fda_event_counts`

Pack: openfda · Endpoint: https://gateway.pipeworx.io/openfda/mcp

Aggregate adverse events by reaction type, patient age, or outcome. Returns top reactions for a drug and event trends over time.

Parameters

Name	Type	Required	Description
`query`	string	yes	OpenFDA search query to filter events before counting. Same syntax as fda_drug_events.
`count_field`	string	yes	Field to count/aggregate by. Examples: “patient.reaction.reactionmeddrapt.exact” (top reactions), “receivedate” (timeline), “serious” (severity breakdown), “patient.drug.openfda.brand_name.exact” (co-reported drugs)

Example call

Arguments

{
  "query": "patient.drug.openfda.brand_name:\"ASPIRIN\"",
  "count_field": "patient.reaction.reactionmeddrapt.exact"
}

curl

curl -X POST https://gateway.pipeworx.io/openfda/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"fda_event_counts","arguments":{"query":"patient.drug.openfda.brand_name:\"ASPIRIN\"","count_field":"patient.reaction.reactionmeddrapt.exact"}}}'

TypeScript (@pipeworx/sdk)

import { Pipeworx } from '@pipeworx/sdk';
const pipeworx = new Pipeworx();

const result = await pipeworx.call('fda_event_counts', {
  "query": "patient.drug.openfda.brand_name:\"ASPIRIN\"",
  "count_field": "patient.reaction.reactionmeddrapt.exact"
});

More examples

{
  "query": "serious:1+AND+receivedate:[20230101+TO+20231231]",
  "count_field": "receivedate"
}

{
  "query": "patient.drug.openfda.generic_name:\"MONTELUKAST\"",
  "count_field": "patient.patientonsetage"
}

Response shape

Always returns: query, count_field, results

Field	Type	Description
`query`	string	The search query used to filter events
`count_field`	string	The field aggregated/counted by
`results`	array	Array of count results by term
`reaction_requested`	string	The reaction term as the caller supplied it, uppercased
`reaction_resolved`	string	The MedDRA preferred term actually used for the filter
`reaction_resolution`	string	How the supplied reaction term mapped onto a MedDRA preferred term. not_a_meddra_preferred_term means the filter matched nothing — counts are zero because the term missed, not because no reports exist
`reaction_resolution_note`	string	Present when word order was corrected; states the substitution made
`reaction_resolution_hint`	string	Present when the term matched nothing; names a working way to discover the real preferred terms
`requested_query`	string	The search query as supplied, when it differs from the resolved query in `query`

Full JSON Schema

{
  "type": "object",
  "properties": {
    "query": {
      "type": "string",
      "description": "The search query used to filter events"
    },
    "count_field": {
      "type": "string",
      "description": "The field aggregated/counted by"
    },
    "results": {
      "type": "array",
      "description": "Array of count results by term",
      "items": {
        "type": "object",
        "properties": {
          "term": {
            "type": "string",
            "description": "The term/value counted"
          },
          "count": {
            "type": "number",
            "description": "Number of occurrences"
          }
        },
        "required": [
          "term",
          "count"
        ]
      }
    },
    "reaction_requested": {
      "type": "string",
      "description": "The reaction term as the caller supplied it, uppercased"
    },
    "reaction_resolved": {
      "type": "string",
      "description": "The MedDRA preferred term actually used for the filter"
    },
    "reaction_resolution": {
      "type": "string",
      "enum": [
        "exact_match",
        "word_order_corrected",
        "not_a_meddra_preferred_term"
      ],
      "description": "How the supplied reaction term mapped onto a MedDRA preferred term. not_a_meddra_preferred_term means the filter matched nothing — counts are zero because the term missed, not because no reports exist"
    },
    "reaction_resolution_note": {
      "type": "string",
      "description": "Present when word order was corrected; states the substitution made"
    },
    "reaction_resolution_hint": {
      "type": "string",
      "description": "Present when the term matched nothing; names a working way to discover the real preferred terms"
    },
    "requested_query": {
      "type": "string",
      "description": "The search query as supplied, when it differs from the resolved query in `query`"
    }
  },
  "required": [
    "query",
    "count_field",
    "results"
  ]
}

Connect

Add this to your MCP client config, or use one-click install buttons:

{
  "mcpServers": {
    "openfda": {
      "url": "https://gateway.pipeworx.io/openfda/mcp"
    }
  }
}

See Getting Started for client-specific install steps.

fda_event_counts