Strategies to increase the sensitivity of pharmacovigilance in Portugal

To evaluate the results of an intervention to improve the number and relevance of reports of adverse drug reactions.

A cluster-randomized controlled trial was conducted with pharmacists working in Northern Portugal, in 2007. After randomization, 364 individuals were placed into the intervention group (261 in telephone interviews and 103 in workshops), while the control group was comprised of 1,103 pharmacists. The following were approached in the educational intervention: the problem of adverse drug reaction, the impact on public health and spontaneous reporting. With regard to relevance, adverse reactions were classified into severe and unexpected. Statistical analysis was performed, based on the intention-to-treat principle; generalized linear mixed models were applied, using the penalized quasi-likelihood method. The pharmacists studied were followed during a period of 20 months.

The intervention increased the rate of spontaneous reporting of adverse reactions three times (RR = 3.22; 95% CI 1.33;7.80), when compared to the control group. The relevance of reporting rose, with an increase in severe adverse reactions by approximately four times (RR = 3.87; 95% CI 1.29;11.61) and in unexpected adverse reactions by five times (RR = 5.02; 95% CI 1.33;18.93), compared to the control group.

During a period of up to four months, educational interventions significantly increased the number and relevance of spontaneous reporting of adverse drug reactions by pharmacists in Northern Portugal.