Summary
Oral anticoagulation, most commonly with warfarin once daily, has long been the main
form of long-term treatment and secondary prevention of thromboembolism. The efficacy
of warfarin has been established in clinical trials, but problems with unstable anticoagulation
with international normalized ratios (INRs) outside the recommended range due to incorrect
dosing, drug and food interactions, and with adherence and persistence have been reported
in practice. Poor adherence and persistence are serious problems because they result
in out-of-range INRs. Many new thromboembolic events, such as strokes, occur when
INRs are out-of-range or after warfarin discontinuation. Among the new anticoagulants
currently being investigated, some offer the possibility of more stable anticoagulation
and weekly administration. Less frequent dosing schedules generally improve adherence.
In many cases, such as bisphosphonate treatment for osteoporosis, and the long-term
treatment of depressive disorders or multiple sclerosis, adherence to, and persistence
with, weekly dosing is improved compared with daily dosing, and most patients prefer
weekly dosing. The advent of novel anticoagulants such as idraparinux with its long
half-life offers hope for improved adherence with anticoagulation, and ultimately
improved outcomes.
Keywords
Idraparinux - anticoagulant - thromboembolism - dose frequency - adherence