Comparison of Three Different Data Sources of Adverse Drug Reactions Using Adverse Drug Reaction Data of Fluorouracil for Gastric Cancer as an Example.

Various sources of information are available for identifying and evaluating adverse drug reactions (ADRs). However, some studies only used the ADR data from spontaneous reporting databases to evaluate the safety of post-marketing drugs. This study was performed to identify an appropriate method for evaluating the safety of post-marketing drugs by comparing the frequencies of ADRs among three datasets: randomized controlled trials, published case reports, and spontaneous reports. Taking ADR data for fluorouracil as an example, we collected the three types of data and extracted their ADR information. All listed ADRs were sorted by frequency from high to low, and the top five ADRs were chosen from each dataset. We assigned an index value of 1.0 to the frequency of one specific ADR (diarrhea) and then calculated the index values of the other ADRs relative to diarrhea. Ten different ADRs were mentioned in the top five ADRs of the three datasets, and only diarrhea and nausea/vomiting were included in all three datasets. The rank orders of the top five ADRs varied among the three datasets. Nausea and vomiting was the most frequent ADR in all three datasets; the remaining ADRs differed among the datasets. There were significant differences in the recording of ADRs and the frequency distributions among the three datasets. A comprehensive and reliable safety profile for post-marketing drugs should not be based on any one source. Spontaneous reports from monitoring institutions provided the most ADR data. Randomized controlled trials and case reports published in the literature can supplement the results from spontaneous reports.