Health

Warfarin Dose Adjustment Calculator (INR Nomogram)

Adjust warfarin maintenance dose from the current INR using the standard nomogram for a target INR of 2.0–3.0. No-bleed ladder: INR<1.5 → +10–20% weekly dose; 1.5–1.9 → +5–15%; 2.0–3.0 → no change; 3.1–3.5 → −5–15%; 3.6–4.0 → −10–20%; 4.1–4.4 → hold 0–1 dose, ~−20%; 4.5–10 → hold + oral vitamin K₁ 1–2.5 mg; >10 → hold + oral vitamin K₁ 2.5–5 mg. Serious/life-threatening bleed at any INR → hold warfarin, vitamin K₁ 5–10 mg IV (slow, 20–30 min) + 4-factor PCC (FFP if unavailable). Optional current weekly dose computes the concrete new weekly and daily dose. Derived from the 9th-edition ACCP Guidelines (Holbrook et al., Chest 2012) and the UW Anticoagulation Clinic nomogram. Valid for adult maintenance therapy at steady state; not for initial induction, DOAC/heparin overlap, or perioperative bridging. Not medical advice.

json· JSON resultOpen tool

Quick start

Call this tool from your code in three languages.

cURL

curl -X POST 'https://api.elysiatools.com/en/api/tools/warfarin-dose-adjustment' \
  -H 'Content-Type: application/json' \
  -d '{"inr":1.7,"weeklyDose":35,"seriousBleed":false,"decimalPlaces":4}'

API reference

Send a POST request with your inputs as JSON. File parameters require a separate upload first.

Endpoint

HTTP

POST https://api.elysiatools.com/en/api/tools/warfarin-dose-adjustment

Parameters

Name	Type	Required	Description
inr	number	Yes	Current INR (prothrombin time ratio). Must be positive.
weeklyDose	number	No	Optional current total weekly warfarin dose in mg. Used to compute the new concrete weekly/daily dose.
seriousBleed	checkbox	No	If checked, the tool switches to the full-reversal pathway (hold + IV vitamin K₁ + PCC) regardless of INR.
decimalPlaces	number	No	—

Response format

JSON result

MCP integration

Add this tool to your Model Context Protocol server so AI agents can list and call it.

Server configuration

Add this block to your MCP client configuration:

mcp.json

{
  "mcpServers": {
    "elysiatools-warfarin-dose-adjustment": {
      "name": "warfarin-dose-adjustment",
      "description": "Adjust warfarin maintenance dose from the current INR using the standard nomogram for a target INR of 2.0–3.0. No-bleed ladder: INR<1.5 → +10–20% weekly dose; 1.5–1.9 → +5–15%; 2.0–3.0 → no change; 3.1–3.5 → −5–15%; 3.6–4.0 → −10–20%; 4.1–4.4 → hold 0–1 dose, ~−20%; 4.5–10 → hold + oral vitamin K₁ 1–2.5 mg; >10 → hold + oral vitamin K₁ 2.5–5 mg. Serious/life-threatening bleed at any INR → hold warfarin, vitamin K₁ 5–10 mg IV (slow, 20–30 min) + 4-factor PCC (FFP if unavailable). Optional current weekly dose computes the concrete new weekly and daily dose. Derived from the 9th-edition ACCP Guidelines (Holbrook et al., Chest 2012) and the UW Anticoagulation Clinic nomogram. Valid for adult maintenance therapy at steady state; not for initial induction, DOAC/heparin overlap, or perioperative bridging. Not medical advice.",
      "baseUrl": "https://api.elysiatools.com/mcp/sse?toolId=warfarin-dose-adjustment",
      "command": "",
      "args": [],
      "env": {},
      "isActive": true,
      "type": "sse"
    }
  }
}

List available tools

After connecting to the SSE endpoint, list the exposed tools:

tools/list

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/list"
}

Call this tool

Invoke the tool by its id, passing arguments built from its parameters:

tools/call

{
  "jsonrpc": "2.0",
  "id": 2,
  "method": "tools/call",
  "params": {
    "name": "warfarin-dose-adjustment",
    "arguments": {
  "inr": 1.7,
  "weeklyDose": 35,
  "seriousBleed": false,
  "decimalPlaces": 4
}
  }
}

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