Inhibitor of zymogen synthesis: WARFARIN
Drugs and Diseases that INCREASE the effects of WARFARIN:
PHARMACOKINETIC mechanisms
- Inhibition of P450 metabolism:
- acute alcohol, allopurinol, cimetidine, ciprofloxacin, erythromicin, fluconazole, fluvoxamine, lovastatin, metronidazole, sulfonamides, trimethoprim-sulfamethoxazole
-
liver disease
- Decreased plasma protein binding:
- clofibrate, gemfibrozil, phenytoin (initially), sulfonamides, trimethoprim-sulfamethoxazole
PHARMACODYNAMIC mechanisms
- Decreased platelet/clotting factor function:
- antiplatelet drugs (e.g., ABCIXIMAB, ASA), HEPARINs, DTIs, etc.
-
blood dyscrasias (hemophilia, von Willebrand’s disease, thrombocytopenia), liver disease, jaundice, elevated temperature, hyperthyroidism
- Decreased availability of vitamin K:
- cephalosporins
- diarrhea, inadequate diet, small bowel disease, steatorrhea