Black box warning contraindicated comedications: concordance among three major drug interaction screening programs.

Background: Black box warnings represent the strongest safety warning that the Food and Drug Administration can issue for a marketed prescription drug. Some black box warnings recommend against coadministration of specific medications due to an increased risk for serious, perhaps life-threatening, effects.

Objective: To determine the level of agreement in presence, clinical severity scores level of documentation ratings, and alert content among 3 leading drug interaction screening programs with regard to contraindicated comedications that are mentioned in black box warnings.