What should be adjusted when a patient is on tetracyclines and warfarin?

When a patient is on tetracyclines and warfarin, it is important to decrease the warfarin dosage. Tetracyclines can interfere with the metabolism of warfarin and may enhance its anticoagulant effect. This interaction can lead to an increased risk of bleeding due to potentiation of warfarin's action.

Monitoring the International Normalized Ratio (INR) is essential in this scenario, as it guides the appropriate dosing of warfarin. If the INR indicates that the patient is at a higher risk for bleeding, it would be prudent to adjust the warfarin dosage downward to ensure the patient maintains a therapeutic anticoagulation level while minimizing the risk of adverse effects.

Maintaining safe anticoagulation levels is crucial in patient management, especially when introducing or continuing medications that may interact with anticoagulants. Therefore, decreasing the dosage of warfarin is the recommended course of action to ensure patient safety.