{
  "id": "medical/contrast-hold-metformin",
  "signature": "AI instructs a diabetic patient to continue metformin during and after iodinated contrast administration without renal function check",
  "signature_zh": "AI指示糖尿病患者在碘造影剂给药期间及之后继续服用二甲双胍，未检查肾功能",
  "regex": "(?i)(metformin|glucophage|biguanide).*(contrast|CT|angiogram|IVP|contrast-induced).*(continue|no need|safe|ignore)",
  "domain": "medical",
  "category": "data_error",
  "subcategory": null,
  "root_cause": "Iodinated contrast can cause contrast-induced nephropathy (CIN), reducing renal clearance of metformin and precipitating lactic acidosis, a rare but fatal complication. Guidelines (ACR, ESUR) require checking eGFR before contrast; if eGFR <30 mL/min/1.73m², metformin must be held 48h before and after contrast; if eGFR 30-60, hold day of contrast and for 48h after.",
  "root_cause_type": "generic",
  "root_cause_zh": "碘造影剂可导致造影剂肾病（CIN），降低二甲双胍的肾脏清除率，诱发乳酸性酸中毒——一种罕见但致命的并发症。指南（ACR、ESUR）要求造影前检查eGFR；若eGFR<30 mL/min/1.73m²，需在造影前后各停用二甲双胍48小时；若eGFR 30-60，造影当日及之后48小时停用。",
  "versions": [],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "Assuming all diabetic patients on metformin need to stop before contrast regardless of renal function",
      "why_fails": "Overly cautious; patients with normal renal function (eGFR >60) can continue metformin safely. The decision depends on eGFR.",
      "fail_rate": 0.5,
      "condition": "",
      "sources": []
    },
    {
      "action": "Telling patient to resume metformin immediately after contrast without checking post-procedure renal function",
      "why_fails": "If CIN develops, the reduced eGFR may still put the patient at risk; guidelines recommend waiting 48h and confirming renal function stable before resuming.",
      "fail_rate": 0.75,
      "condition": "",
      "sources": []
    },
    {
      "action": "Using BUN or creatinine alone without calculating eGFR",
      "why_fails": "Creatinine alone is misleading in elderly or low muscle mass patients; eGFR (CKD-EPI equation) is the standard for metformin dosing decisions.",
      "fail_rate": 0.65,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "Check eGFR before contrast. If eGFR >60 mL/min/1.73m²: continue metformin normally. If eGFR 30-60: hold metformin on day of contrast and for 48h after, then recheck eGFR. If eGFR <30: hold metformin 48h before and 48h after contrast, recheck eGFR before resuming.",
      "success_rate": 0.9,
      "how": "Check eGFR before contrast. If eGFR >60 mL/min/1.73m²: continue metformin normally. If eGFR 30-60: hold metformin on day of contrast and for 48h after, then recheck eGFR. If eGFR <30: hold metformin 48h before and 48h after contrast, recheck eGFR before resuming.",
      "condition": "",
      "sources": []
    },
    {
      "action": "For emergency contrast where pre-procedure eGFR is unavailable, hold metformin immediately, administer contrast, and check eGFR post-procedure. Resume metformin only if eGFR >30 and no evidence of CIN (creatinine rise <0.3 mg/dL).",
      "success_rate": 0.8,
      "how": "For emergency contrast where pre-procedure eGFR is unavailable, hold metformin immediately, administer contrast, and check eGFR post-procedure. Resume metformin only if eGFR >30 and no evidence of CIN (creatinine rise <0.3 mg/dL).",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [
    "Check eGFR before contrast. If eGFR >60 mL/min/1.73m²: continue metformin normally. If eGFR 30-60: hold metformin on day of contrast and for 48h after, then recheck eGFR. If eGFR <30: hold metformin 48h before and 48h after contrast, recheck eGFR before resuming.",
    "For emergency contrast where pre-procedure eGFR is unavailable, hold metformin immediately, administer contrast, and check eGFR post-procedure. Resume metformin only if eGFR >30 and no evidence of CIN (creatinine rise <0.3 mg/dL)."
  ],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": "https://www.acr.org/-/media/ACR/Files/Clinical-Resources/Contrast_Media.pdf",
  "official_doc_section": null,
  "error_code": "ACR-2024-MET",
  "verification_tier": "ai_generated",
  "confidence": 0.86,
  "fix_success_rate": 0.82,
  "resolvable": "true",
  "first_seen": "2024-05-20",
  "last_confirmed": "2024-06-01",
  "last_updated": "2024-06-01",
  "evidence_count": 1,
  "tags": [],
  "locale": "en",
  "aliases": []
}