Abstract
Adverse drug reactions (ADR) caused by inappropriate prescription are responsible for major socioeconomic loss. Drug-drug interactions (DDI) has been recognized as a major part of ADRs and, therefore, healthcare professionals should prevent possible DDIs to minimize preventable ADRs. This study aimed to examine DDI information in drug information references and Korea Food & Drug Administration (KFDA) drug labeling information. Drug ingredients from the formulary of Health Insurance Review and Assessment Service in Korea (HIRA) were included for the study. DDI information source used for the study were Micromedex Drugdex and Drug Information Facts (DIF) with the DDI severity level of "moderate" or more. The DDI information in KFDA drug labeling were collected and compared. Drug ingredients were classified with KFDA Drug Classification and ATC Classification of WHO for the analysis. Among the total 1,355 drug ingredients satisfying inclusion criteria, 738 ingredients involved at least one DDI, which was described in Micromedex and/or DIF. Drug Ingredients of 176 involved DDI only described in KFDA drug labeling, but not Micromedex nor DIF. Drug ingredients of 35 which DDIs were described in Micromedex or DIF did not have DDI based on KFDA drug labeling. Micromedex and DIF retrieved 7,582 and 3,071 DDIs, respectively 57.6% and 58.5% of DDIs were also described in KFDA drug labeling. Central nervous system (CNS) drugs, cardiovascular system (CVS) drugs and the antiinfectives appeared to have higher frequency of DDIs among all drug classes. The highest number of DDIs with high severity level ("contraindicated" or "major") were the DDIs of CNS drugs. The antiinfectives are the second drug group having serious DDIs. The DDI pairs of the CNS drug and the antiinfective had the highest contraindication risk (13.6%). DDI information from Micromedex and DIF were not consistent with the result that only 465 ingredients' DDIs are common in both literature (total DDI numbers were 715 vs 488, respectively). And 1,652 DDI information are common in both references among 7,582 vs 3,071 DDIs, respectively. Only 55.2% of DDI information in the database contained in the KFDA drug labeling. Prescribers and pharmacists should pay attention to the drugs for CV system, CNS and infections because of higher risk of possible DDIs compared to other drug classes. KFDA drug labeling is not likely to be recommended as a good information source for DDI due to significant inconsistency of information. Drug information providers should be aware that DDI information from different sources are not consistent and therefore multiple references should be used.
