The lack of knowledge about the voluntary reporting system of adverse drug reactions as a major cause of underreporting: direct survey among health professionals

Background: Underreporting suspected adverse drug reactions (ADRs) is one of the main problems that face the pharmacovigilance (PhV) systems based on yellow card schemes.

Objectives: To measure the knowledge level on the suspected ADR voluntary reporting system among physicians and pharmacists in Venezuela and to study its relationship with different variables.

Methods: A population-based, anonymous, and self-administered questionnaire was addressed to health professionals along the national territory of Venezuela. An algorithm was developed to classify the knowledge level on the voluntary reporting system.

Results: Taken as a whole, the level of knowledge on the voluntary reporting system was "poor." Among the 515 participant physicians, 62.3% (95%CI = 58.0-66.5%) had a "poor" level of knowledge; PhV was associated with "control" of medicines use, and only 24.7% had ever reported a suspected ADR. "Medical specialty" was the only variable that showed a relationship with the knowledge level (p = 0.0041). Among the 78 participant pharmacists, 66.7% had a "poor" knowledge level (95%CI = 55.1-76.9%).

Conclusions: The knowledge level on the voluntary reporting system among physicians and pharmacists in Venezuela is poor. These results strengthen the hypothesis that being unaware of the adverse effects of medicines and not knowing the existence of a PhV system is a major cause of underreporting. A careful study of the actual knowledge of PhV could be the basis to set up interventions specifically designed to overcome misleading concepts and to improve the reporting rate at a national level.