In patients taking anticoagulants, which of the following should be regularly monitored?

Regular monitoring of prothrombin time (PT) is essential for patients taking anticoagulants because this test evaluates the clotting ability of blood and helps ensure that the patient's blood is within the desired therapeutic range. Anticoagulants work by inhibiting certain factors in the coagulation cascade, thereby preventing excessive clot formation. However, if the anticoagulant effect is too strong, it can lead to an increased risk of bleeding; if it's too weak, it may not provide adequate protection against thromboembolic events such as strokes or deep vein thrombosis.

Prothrombin time is particularly important for those on vitamin K antagonists like warfarin, as it reflects the effectiveness of the drug in prolonging the clotting time. Regular monitoring allows healthcare providers to adjust dosages appropriately to maintain a balance between efficacy and safety.

The other options, such as monitoring blood cholesterol levels, blood pressure, or heart rate variability, while important for overall patient health, do not specifically relate to the direct impact of anticoagulant therapy on blood coagulation and the associated risks. Therefore, prothrombin time stands out as the critical parameter that must be routinely assessed in patients receiving anticoagulants.