Comparison of two databases to detect potential drug–drug interactions between prescriptions of HIV/AIDS patients in critical care G. V. Ramos PharmD, L. Guaraldo PharmD PhD, A. M. Japiass u MD PhD and F. A. Bozza MD PhD Evandro Chagas Clinical Research Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil Received 25 August 2014, Accepted 14 September 2014 Keywords: AIDS, critically ill, drug prescriptions, drug–drug interactions, intensive care unit, pharmacovigilance SUMMARY What is known and objective: Adverse drug events (ADE), common and underestimated in ICU patients, have direct consequences on length of stay, mortality and hospital costs. Critically ill patients with HIV/AIDS are at a high risk of ADE because of their need for multiple drug therapies. ADE can be prevented, especially by the identification of potentially harmful drug–drug interactions (DDIs). Electronic databases are useful tools for the investigation of DDIs to avoid potential ADEs, thereby increasing patient safety. The purpose of this study was to compare the classification and severity rating of potential adverse drug interactions seen in the prescriptions for patients with HIV/AIDS in two databases, one with free access (Drugs.com TM ) and another requiring payment for access (Mi- cromedex â ). Methods: A cross-sectional retrospective study of the prescrip- tions issued for 40 ICU HIV/AIDS patients on mechanical ventilation, admitted for more than 48 h, in a referral hospital for infectious diseases in Rio de Janeiro, Brazil, was undertaken. One prescription was reviewed each week for each patient from the second day after admission. A list of all drug–drug interactions was generated for each patient using the two drug–drug interactions databases. The weighted kappa index was estimated to assess the agreement between the classifica- tions of DDIs identified by both databases and qualitative assessment made of any discordant classification of recorded drug–drug interactions. Results and discussion: Of the 106 prescriptions analysed, Micromedex â and Drugs.com identified 347 and 615 potential DDIs, respectively. A predominance of moderate interactions and pharmacokinetic interactions was observed. The agreement between the databases regarding the severity rating was only 68Á3%. The weighted kappa of 0Á44 is considered moderate. Better agreement (82Á4%) was observed in the classification of mechanism of interaction, with a weighted kappa of 0Á61. What is new and Conclusion: DDIs are common between the prescriptions of patients with HIV/AIDS admitted to the ICU. Although both databases were able to identify the clinically relevant DDIs, we observed a significant discrepancy in the classification of the severity of DDIs in the two bases. The free access database could serve as an alternative to the identification of DDIs in resource-limited settings; however, there is a need for better evidence-based assessments for your use on clinical management of more serious DDIs. WHAT IS KNOWN AND OBJECTIVE The long-term survival of patients with human immunodefi- ciency virus (HIV) has improved markedly since the introduction of highly active antiretroviral therapy (HAART). 1,2 UNAIDS/ WHO estimated that around 34 million of people were living with HIV worldwide at the end of 2010. 3 This number is expected to continue to grow, in particular in third-world urban centres. This setting presents multiple challenges in establishing acceptable, efficacious and minimally toxic regimens, especially in the treatment of patients with HIV/AIDS with severe infections. 4 Patients with HIV/AIDS presenting acute and severe illnesses can require multiple therapeutic schemes simultaneously, pre- disposing them to significant drug interactions and adverse drug events (ADE). 5 These events can affect patient’s outcome and hinder clinical management, increasing hospital stay and costs. 6,7 Additionally, patients with HIV have a much greater rate of ADE to many drug classes, such as antimicrobials and anticon- vulsants, including severe and life-threatening hypersensitivity reactions. 8 Therefore, critically ill patients with HIV/AIDS are prone to ADE, and their drug prescriptions should be moni- tored. ADE can be prevented through the identification of relevant drug–drug interactions (DDIs). The term DDIs refers to the presence of a second drug altering the effectiveness or toxicity of the first drug. Clinically relevant DDIs can be predicted from the drug’s properties, the method of drug administration and patient-specific parameters. Electronic databases are useful tools for to investigate and to prevent potential ADE, increasing patient safety. 9 Severely ill patients are especially susceptible to potential interactions, and the estimated incidence of potential interactions in the ICU is as high as 287Á5 per 100 admissions. 10 However, many of the reference databases in pharmacovigi- lance, such as Micromedex â and Lexi-Interact TM , require pay- ment for access, restricting their use to a limited number of institutions. Therefore, we propose free access to electronic tools as an alternative for the management of DDIs in healthcare facilities with limited resources, especially in lower-income countries. Therefore, the aim of this study was to compare the identifica- tion and classification of potential DDIs between prescriptions for patients with HIV/AIDS in the ICU using two databases, one with free access (Drugs.com TM ) and another requiring payment for access (Micromedex â ). Correspondence: Fernando Augusto Bozza, Oswaldo Cruz Foundation – Av. Brasil, 4365 – Manguinhos, Rio de Janeiro, RJ 21040-900, Brazil. Tel./fax: 21 3865959; e-mail: bozza.fernando@gmail.com or fernando. bozza@ipec.fiocruz.br © 2014 John Wiley & Sons Ltd 63 Journal of Clinical Pharmacy and Therapeutics, 2015, 40, 63–67 doi: 10.1111/jcpt.12222