Effect of Fasting in Patients Taking Acenocoumarol

Abstract

Anticoagulation with acenocoumarol is influenced by dietary changes but the effect of fasting on acenocoumarol therapy is unknown. Objectives: To study changes in international normalized ratio (INR) and the percentage of time within therapeutic range (%TTR) before and during Ramadan. Methods/Patients: In this prospective study, weekly INR readings were taken from participating patients during two study periods: before and during Ramadan. Readings were blinded to patients and their primary physicians except for when pre-set study endpoints were reached. Results: Among 128 participating patients, mean INR increased by 0.25 (P = 0.006) during Ramadan from the pre-Ramadan month. There was no significant difference (P = 0,02) in mean INR between the non-Ramadan months. No bleeding or thrombotic events were recorded. Conclusion: Fasting significantly increases the mean INR of medically stable patients taking acenocoumarol and the likelihood of having an INR above therapeutic targets.