Table 3.

Limitations of warfarin.

Frequent monitoring necessitating regular clinic attendance Narrow therapeutic window Slow onset and offset of action, requiring 3–6 days to reach therapeutic levels Long half-life Numerous drug and dietary interactions Genetic polymorphishms exist which confer increased sesnsitivity or resistance to warfarin Unpredictable pharmacodynamics and pharmacokinetics leading to inter and intra-individual variability in dose and metabolism