Phenprocoumon

Uses & side effects

Product-specific side effects await source review.

Drug interactions

Anticoagulant and antiplatelet medications in horses interact most severely with Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) and other clotting-altering agents, drastically escalating the risk of life-threatening gastrointestinal hemorrhage or internal bleeding. Anticoagulants (like heparin and historical use of warfarin) and antiplatelets (like aspirin and clopidogrel) are utilized in equine medicine to prevent or treat laminitis, jugular thrombophlebitis, disseminated intravascular coagulation (DIC), and endotoxemia. Because horses are naturally prone to gastric ulcers and colon issues, combining therapies that compromise clotting and mucosal protection demands extreme caution.The primary drug-to-drug interactions for equine anticoagulants and antiplatelets include:1. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)Medications: Phenylbutazone (“Bute”), Flunixin Meglumine (“Banamine”), Firocoxib (Equioxx).The Interaction: Severe pharmacodynamic interaction. NSAIDs inhibit cyclooxygenase (COX) enzymes, which diminishes the production of protective prostaglandins in the horse's gut and kidneys. Concurrently, they temporarily disrupt blood platelet function.Clinical Impact: Critical risk. When stacked with an anticoagulant like heparin, the protective lining of the gastrointestinal tract weakens while the blood's ability to clot is suppressed. This combination frequently causes severe, life-threatening gastrointestinal bleeding, bleeding into joints, or internal bleeding from injection sites.2. Multi-Agent Antithrombotic StackingMedications: Combining Heparin (Unfractionated or Low-Molecular-Weight) with Aspirin or Clopidogrel.The Interaction: Dual antiplatelet/anticoagulant therapy over-suppresses different pathways of the clotting cascade (e.g., heparin inactivates thrombin, while clopidogrel blocks platelet P2Y12 receptors).Clinical Impact: High risk. While sometimes intentionally utilized in critical hospital settings for severe jugular thrombosis, it creates a narrow therapeutic window. The slightest trauma can cause severe, uncontrolled hematomas or continuous bleeding.3. Heparin and Protamine Sulfate (Antagonism)Medications: Protamine Sulfate.The Interaction: Direct chemical neutralization. Protamine is a strongly basic protein that binds directly to strongly acidic heparin molecules, creating a stable, inactive salt complex.Clinical Impact: While technically an interaction, this is highly beneficial. Protamine acts as the specific antidote to reverse heparin overdose or treat severe hemorrhage induced by heparin therapy.4. Cytochrome P450 Modulators (with Clopidogrel or Warfarin)Medications: Cimetidine, Omeprazole, certain Macrolide antibiotics.The Interaction: Antiplatelets like clopidogrel are prodrugs that require activation by hepatic cytochrome P450 enzymes to become effective. Conversely, historical oral anticoagulants like warfarin are broken down by these same liver enzymes.Clinical Impact: Moderate to High.If a horse receives an enzyme inhibitor (like cimetidine) alongside clopidogrel, the horse will fail to activate the drug, rendering the anti-clotting therapy useless.If a horse is on warfarin, enzyme inhibitors can trigger a rapid, toxic accumulation of the anticoagulant, inducing spontaneous systemic bleeding.

Contraindications