Background:

Vitamin K antagonist medications (VKA) are essential for the prevention of thromboembolic events, but their effectiveness is influenced by multiple factors, such as the type of medication chosen.

Aim:

To evaluate the efficacy in anticoagulant control of the bioequivalent and non-bioequivalent drugs of acenocoumarol compared to the reference drug. To evaluate the efficacy of warfarin bioequivalents available in Chile. To contrast the overall anticoagulant control efficacy between acenocoumarol and warfarin.

Material and Methods:

The results of 69333 outpatient oral anticoagulation controls were analyzed. Patient were separated in groups according to the drug that they used. Subsequently, the proportions of controls outside the range for each of acenocoumarol and warfarin bioequivalent drugs were compared. Acenocoumarol non-bioequivalent drugs were also compared with the reference drug. Acenocoumarol was compared with warfarin.

Results:

Acenocoumarol bioequivalent drugs and the reference drug had a similar proportion of controls outside the range (Odds ratios (OR) 0.812; 0.969; 0.974 and 0.963). Non-bioequivalent drugs had a higher proportion than the reference drug (OR 1.561 and 2.037). Both warfarin brands have a similar proportion of controls outside of the range (OR 1.050). Acenocoumarol compared to warfarin had a significant higher proportion of controls outside the range (OR 1.191).

Conclusions:

The pharmacological presentation of vitamin K antagonists could influence anticoagulant control. Therefore, it is not prudent to switch these presentations frequently.