Comparison of control and stability of oral anticoagulant therapy using acenocoumarol versus phenprocoumon

Abstract

Variability in the control of oral anticoagulant therapy has been associated with a heightened risk of complications. We compared control of anticoagulation between two commonly used coumarins, phenprocoumon and acenocoumarol, and among anticoagulation clinics. All qualifying patients were managed at six regional anticoagulation clinics in the Netherlands. This retrospective cohort study compiled data during a three-year period from a computerised dosing and management system. Anticoagulation control was expressed as the percent of time within the therapeutic range and stability expressed as the time-weighted variance in the international normalised ratio (INR). Data were available for 22,178 patients of whom 72% were treated with acenocoumarol. INRs of patients who received phenprocoumon were within the therapeutic range 50% of the time compared with 43% for acenocoumarol (OR 1.32, 95% CI 1.24-1.41). Moreover, patients on phenprocoumon required 15% fewer monitoring visits and had more stable INR values. These observations were consistent for all six clinics. There were also sizable differences between the clinics with respect to control and stability of anticoagulation that were stable from year-to-year and were unrelated to the drug used. With its longer half-life of three to five days, phenprocoumon produces more stable anticoagulation than acenocoumarol and should generally be the drug of choice when these are the available choices. The differences observed among clinics suggest that certain clinics employ policies and practices resulting in better control of anticoagulation.

Quality of oral anticoagulation with phenprocoumon in regular medical care and its potential for improvement in a telemedicine-based coagulation service – results from the prospective, multi-center, observational cohort study thrombEVAL

“…This may indeed enable more stable anticoagulation control with phenprocoumon as compared to the shorter acting products. As previously described, patients on phenprocoumon seem to require fewer monitoring visits and have more stable INR values than patients treated with short-acting VKA [ 29 ]. In addition, effects of VKA-relevant genetic polymorphisms, e.g., CYP2C9 or VKORC-1 polymorphism [ 30 , 31 ], might be less pronounced in patients treated with phenprocoumon [ 16 ].…”

Phenprocoumon Dose Requirements, Dose Stability and Time in Therapeutic Range in Elderly Patients With CYP2C9 and VKORC1 Polymorphisms

“…However, until now this association is not fully understood and there may be arguments underlining this hypothesis. Phenprocoumon has a longer half-life compared to warfarin and acenocoumarol (Ufer, 2005) and has been shown to produce a more stable anticoagulation (Fihn et al, 2003). Consequently, it may be hypothesized that an additionally slower metabolism due to CYP2C9 polymorphisms could enhance this effect, also because the lower dosages in polymorphism carriers are expected to result in smaller peak/ trough fluctuations.…”

Effect of switching from acenocoumarol to phenprocoumon on time in therapeutic range and INR variability: A cohort study

“…Additionally, TTR was dichotomised with a cut-off of 65% because patients with a TTR � 65% have a favourable risk profile for bleeding and thrombosis [1]. INR variability was calculated using Fihn's method [5] (equation). Furthermore, we determined the mean INR (without interpolation), the mean time between INR measurements, and the mean VKA dose in milligrams.…”