In this class of drugs we distinguish:
- Warfarin
- dicumarol
- phenprocoumon
- phenindione
- Phytonadione (Vit. K1)
Warfarin
Antithrombotic coumarin drug, also used as rodenticide, naturally occurring as bishydroxycoumarin and synthesized as dicumarol.
Clinical use warfarin consists of a racemic mixture characterized by equal aliquots of two enantiomorphs. S-warfarin levorotation is four times more potent than dextrorotatory R-warfarin.
Cumarinic anticoagulants block the gamma-carboxylation of some glutamic residues of prothrombin and factors VII, IX and X as well as the endogenous anticoagulant protein C.
phenprocoumon
Cumarinic anticoagulant drug similar and similar to walfarin and dicumarol.
Vitamin K antagonists outside of walfarin are rarely used because of their less favorable pharmacological properties or greater toxicity. Phenprocumon has a long half-life (6 days). In Italy it is not present in any specialty.
Clinically proven interactions of oral anticoagulants
Oral anticoagulants exhibit inducible metabolism properties, with the possibility of inhibiting metabolism.
Possibility of elevated binding to plasma proteins.
The anticoagulant effect is altered by drugs that modify the synthesis or catabolism of coagulation factors.
Drugs that can increase the anticoagulant effect:
- Amiodarone
- quinidine
- Cimetidine
- Ciprofloxacin
- clofibrate
- Chloramphenicol
- Danazol
- Disulfiram
- D-Thyroxine
- Erythromycin
- NSAIDs
- Phenylbutazone
- Fluconazole
- Gemfibrozil
- Lovastatin
- metronidazole
- miconazole
- Thyroid hormones
- Propafenone
- Salicylates
- Anabolic steroids
- sulfa
- sulfinpyrazone
- Trimethoprim-sulfamethoxazole
Drugs that can decrease the anticoagulant effect
- aminoglutethimide
- barbiturates
- Carbamazepine
- cholestyramine
- Phenytoin
- glutethimide
- nafcillin
- primidone
- Rifampin
Effects of coumarin anticoagulant drugs on other drugs
- Phenytoin
- Oral hypoglycemic agents
