Objective:

To analyze the interaction between acenocoumarol and levofloxacin in the elderly. We also assessed how hypoalbuminemia affects international normalized ratio variation.

Method:

Retrospective study carried on elderly institutionalized patients who were prescribed levofloxacin concomitantly with acenocoumarol. International normalized ratio variation during levofloxacin treatment was analyzed with the t-Student test. Correlation between albuminemia and international normalized ratio variation was calculated using Pearson´s correlation coefficient.

Results:

The mean international normalized ratio previous to treatment with levofloxacin was 2.5 (standard deviation: 0.6) and during treatment it was 4.7 (standard deviation: 1.9) (p < 0.05). In 54.3% of the cases, the international normalized ratio value was equal to or greater than 4.5. Not linear association between albuminemia and international normalized ratio increase was found using Pearson´s test (R = -0.16).

Conclusions:

In more than half of the occasions international normalized ratio raised to clinically rellevant values (≥ 4.5). No influence of hypoalbuminemia in the increase in international normalized ratio was shown.