# Search drug formulary evidence
URL: https://backworkhealth.com/docs/api/searchDrugFormularyEvidence

Search commercial pharmacy-benefit evidence from CVS Caremark, Express Scripts, and UnitedHealthcare / Optum Rx.

**Endpoint:** `GET /api/v1/drugs/formulary`

**Availability:** Live in production.

**Authentication:** API key in `Authorization: Bearer <key>` with the `read` scope.

Search commercial pharmacy-benefit evidence from CVS Caremark, Express Scripts, and UnitedHealthcare / Optum Rx. Records are informational; verify current coverage, utilization management, and member-specific benefits with the payer.

**Parameters**

* `q` (query, required): Drug name or therapeutic category search query
* `payer` (query): Optional payer/PBM source filter
* `limit` (query): Maximum results per source

**Example request**

```bash
curl -X GET "https://backworkhealth.com/api/v1/drugs/formulary?q=metformin&payer=all" \
  -H "Authorization: Bearer $BACKWORK_API_KEY"
```

**Example response** (`200`)

```json
{
  "success": true,
  "data": [
    {
      "source": "cvs_caremark",
      "payer_name": "string",
      "pbm_name": "string",
      "formulary_name": "string",
      "plan_year": 0,
      "effective_date": "string",
      "drug_name": "string",
      "matched_text": "string",
      "therapeutic_category": "string",
      "drug_class": "string",
      "tier": "string",
      "coverage_status": "string",
      "requirements": {
        "prior_authorization": true,
        "step_therapy": true,
        "quantity_limit": true,
        "specialty": true,
        "text": "string",
        "codes": [
          "string"
        ]
      },
      "alternatives": "string",
      "preferred_alternatives": "string",
      "source_url": "string",
      "source_page": 0
    }
  ],
  "meta": {
    "request_id": "string",
    "timestamp": "2026-01-15T10:30:00Z",
    "search": {
      "query": "string",
      "payer": "string"
    },
    "counts": {
      "cvs_caremark": 0,
      "express_scripts": 0,
      "uhc": 0,
      "total": 0
    },
    "limit_per_source": 0,
    "attributions": {
      "disclaimer": "string",
      "cpt": "string",
      "loinc": "string",
      "cms": "string",
      "payer_data": "string",
      "negotiated_rates": "string"
    },
    "disclaimer": "string"
  }
}
```