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One selection filters the source overview, clinical facts, reports and dose calculator. Literature references are not species-filtered.
Choose one species for its overview and dose calculator, or all species to browse the full evidence.
Source overview
Recorded excerpts for one species. Each dose remains a separate source entry; no regimen is selected.
Choose one species to view its source overview. All-species evidence remains available below.
View full clinical evidence and sources ↓Clinical evidence
Pending clinical review (PROPOSED)Rule-based (RULE_BASED)— applies to the facts and dose entries in this species selection; individual source records retain their own status.
Indications2
Long-term oral antithrombotic (venous thrombosis/PTE maintenance, ATE prevention historically) — controversial and largely displaced by LMWHs/clopidogrel (FAT CAT era)
DogCatExtra-label (EXTRA_LABEL)2 source records · View provenance
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Original excerpt: Long-term oral antithrombotic (venous thrombosis/PTE maintenance, ATE prevention historically) — controversial and largely displaced by LMWHs/clopidogrel (FAT CAT era) — Extra-label (human drug)
- Cat · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Original excerpt: Long-term oral antithrombotic (venous thrombosis/PTE maintenance, ATE prevention historically) — controversial and largely displaced by LMWHs/clopidogrel (FAT CAT era) — Extra-label (human drug)
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Dose regimens3
This calculator performs arithmetic only on the sourced dosing field shown for each result — it does not verify the field's accuracy, does not select which field to use for a patient, and does not replace a veterinarian's order. Not for clinical use. Confirm every result against the primary source before dispensing.
Choose one species above to view its dose calculator.
Adverse effects3
Hemorrhage (dose-related; lag-masked) — The effect and the danger
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Single-dose toxicity: 5–50 mg/kg — Acute ingestion
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Cumulative: 1–5 mg/kg × 5–15 d (dog); 1 mg/kg × 7 d (cat) — The rodenticide-adjacent math
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Monitoring1
PT/INR at initiation frequently then q2–4 wk minimum — the monitoring burden that killed veterinary enthusiasm; CBC/bleeding signs
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Monitoring Parameters · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Contraindications1
Active/preexisting hemorrhage, pregnancy, eye/CNS surgery planning, blood dyscrasias, uncontrolled hypertension, hepatic insufficiency, aneurysm, pericardial effusion
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Contraindications & Warnings table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Precautions4
The 2–5 day lag works both directions — hold monitoring through changes
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Contraindications & Warnings table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
The mirror-image of the rodenticide file: warfarin IS long-acting-rodenticide pharmacology, dosed intentionally — and its rescue (vitamin K1 + plasma) is the same protocol in reverse.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Why it lost: unproven mortality benefit + monitoring expense + bleeding risk + the FAT CAT trial (warfarin no better than aspirin in feline ATE, more bleeding) → LMWH/clopidogrel era.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
The initiation paradox (protein C falls before IIa) explains the heparin bridge — warfarin briefly THICKENS the blood.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Interactions1
The longest interaction list in medicine: NSAIDs/aspirin (bleeding), metronidazole/trimethoprim-sulfa/chloramphenicol (↑ warfarin), phenobarbital/rifampin (↓ warfarin), thyroid hormone (↑ effect), vitamin K in diets (variable ↓) — Screen every new drug
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Pharmacokinetics3
Mechanism — Inhibits vitamin-K epoxide reductase → blocks synthesis of II, VII, IX, X (+ proteins C/S) — existing factors must decay first → 2–5 day lag to effect AND to toxicity
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Protein C dip early — Early protein-C fall → transient hypercoagulability — never warfarin alone at initiation
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Antidote — Vitamin K1 (phytonadione) + plasma (see vitamin-k1.md — the rodenticide mirror-image)
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Pregnancy / lactation considerations1
Teratogenic — contraindicated.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 877–879 — Pregnancy & Lactation · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Literature references19
References are linked to this drug. Species applicability is not recorded here, so the species filter does not narrow this list. Imported dates do not retain their original precision; confirm dates in the original citation.
- A reproducible rat model for warfarin studies: Prothrombin time assessment with minimal blood using the CoaguChek XS and determination of an effective warfarin dosage.
Study summary not available in the imported record. Open the original citation to review the study.
- An ordinary differential equation-based integrated pharmacokinetic-pharmacodynamic model for predicting anticoagulant responses to warfarin and diphacinone across rodent and bat species.
Study summary not available in the imported record. Open the original citation to review the study.
- Emerging Insights of Management of Venous Thromboembolism in Patients With Cancer.
Study summary not available in the imported record. Open the original citation to review the study.
- Isomer-Dependent Pharmacokinetic Behavior and VKOR Interactions of Second-Generation Anticoagulant Rodenticides: An Integrated In Vivo-In Vitro-In Silico Investigation.
Study summary not available in the imported record. Open the original citation to review the study.
- Improving Genotype Imputation in High-Dimensional Pharmacogenomics Using Multiple Imputation: Evaluation with Machine Learning Approaches.
Study summary not available in the imported record. Open the original citation to review the study.
Sources: PubMed, National Library of Medicine; Plumb DC. Plumb's Veterinary Drug Handbook. 7th ed. PharmaVet Inc; 2011.
Owner information handout
Plain-language medication information to review with the owner. Open the handout to print it or download a PDF.