| Warfarin | Non-fractionated heparin | Low molecular weight heparin (LMWH) |
---|---|---|---|
Mechanism of action | Block of synthesis of vitamin K-dependent coagulation factors (II, VII, IX and X) | Bond with AT-III and inhibition of II, VII, IX, X, XI, XII coagulation factors | Bond with AT-III and inhibition of II, VII, IX, X, XI, XII coagulation factors |
Therapeutic indications | Medium to giant aneurysms, history of heart attack, history of intra-aneurysm thrombosis | Aneurysms with high thrombotic risk, before starting therapy with warfarin | Same as non-fractioned heparin |
Dosage | Initial dose of 0.05–0.12 mg/kg/day, progressively increased over 4–5 days to obtain an INR between 2.0 and 2.5 | Initial intravenous dose: 50 U/kg in 10 min or more, followed by 20–25 U/kg/hour to maintain aPTT between 60 and 85″ |  |
Side effects | Bleeding (epistaxis, gum bleeding, intracranial and intra-abdominal hemorrhage), embryopathies (dysostosis, dyschondroplasia, microcephaly) | Hemorrhage, thrombocytopenia, hepatic dysfunction, rash, diarrhea, hair loss, osteoporosis | Same as non-fractionated heparin, but less osteoporosis |
Interactions | Reduced efficacy with chlorophyll contained in green and yellow vegetables (with high contents of vitamin K), vitamin K-enriched milk, phenobarbital, carbamazepine, rifampicin; increased efficacy if breastfeeding, use of erythromycin, fluconazole, corticosteroids, amiodarone | None | None |