What characterizes the range between effective and toxic drug levels of Warfarin?

The characteristic that defines the range between effective and toxic drug levels of Warfarin is the narrow therapeutic index. A narrow therapeutic index indicates that there is a small margin between the minimum effective dose and the minimum toxic dose of a medication.

In the case of Warfarin, it requires careful monitoring, often involving regular INR checks, to ensure that blood clotting levels remain within the safe and effective range. The dosing can be sensitive to various factors, including diet, other medications, and individual patient factors, which can increase the risk of adverse effects if the dosage is slightly too high. This narrow window of safety necessitates close clinical supervision and precise dosing to avoid potentially serious complications such as bleeding or thrombosis.

The other options suggest wider margins or standards in therapeutic indices that do not accurately capture the pharmacokinetics of Warfarin. Understanding this concept is essential for safe prescribing and monitoring when using anticoagulants like Warfarin in clinical practice.