74 VOLUME 87 NUMBER 1 | JANUARY 2010 | www.nature.com/cpt ARTICLES nature publishing group Adverse drug reactions (ADRs) are considered to be among the leading causes of morbidity and mortality. An estimated 5–25% of hospital admissions are due to ADRs, 1,2 and ~6–15% of hos- pitalized patients experience serious ADRs (SADRs), causing signiicant prolongation of hospital stay. 3,4 Moreover, fatal ADRs are estimated to occur in ~0.31% of hospitalized patients, and complications from drug therapy constitute the most common adverse events in hospitalized patients. 5 he detection and reporting of SADRs have become impor- tant components of monitoring and evaluation activities per- formed in hospitals. 6 he World Health Organization, 7 the US Food and Drug Administration, 8 and the European Medicines Agency 9 have communicated the need to evaluate the efects (both beneficial and harmful) of drugs and to continually improve the use of drugs so as to provide appropriate, safe, and efective drug therapies. he detection, reporting, and prevention of SADRs are important aspects of this mission. With increasing competition and regulatory pressures to con- tinually improve the provision of health care, hospitals must improve the detection of SADRs so as to prevent negativ patient outcomes. At present, most hospitals participate in pharmacovigila through spontaneous reporting systems. However, sponta reporting systems have limitations such as the diiculty of r nizing ADRs, the uncontrolled nature of the reporting meth and underreporting. For these reasons, retrospective and pr tive surveillance methods are considered to be more efectiv spontaneous reporting systems. 10 Given the poor documenta- tion of ADRs in medical case notes, retrospective systems underestimate the burden of ADRs in hospitals. 11 Prospective sys- tems ofer two main advantages that are unavailable in ret tive systems: high-quality information regarding an advers and early identiication of a potential ADR before it exacerb the clinical condition of an individual patient. hus, implem tion of a prospective system can address the most importa unresolved problem during the course of drug therapy. In recent decades, the availability of large, computerized cal databases linked to electronic medical records (EMRs) 1 Clinical Pharmacology Service, La Paz University Hospital, School of Medicine, Universidad Autónoma de Madrid, Madrid, Spain. Correspondence: E Ramirez (elena.ramirez@uam.es) or J Frias (jesus.frias@uam.es) Received 20 March 2009; accepted 7 August 2009; advance online publication 4 November 2009. doi:10.1038/clpt.2009.185 A Pharmacovigilance Program From Laborato Signals for the Detection and Reporting of Serious Adverse Drug Reactions in Hospitalized Patients E Ramirez 1 , AJ Carcas 1 , AM Borobia 1 , SH Lei 1 , E Piñana 1 , S Fudio 1 and J Frias 1 The detection and reporting of serious adverse drug reactions (SADRs) have become important co monitoring and evaluation activities performed in hospitals. We present the implementation of a p pharmacovigilance program based on automatic laboratory signals (ALSs) at a hospital. We also re general findings after the first year of operation of the program, which involved ALSs that indicate agranulocytosis, aplastic anemia, liver injury, thrombocytopenia, hyponatremia, and rhabdomyoly hospitalizations during the year was 54,525, and 1,732 patients experienced at least one ALS. The medical records (EMRs) showed that no alternative cause (i.e., no non-SADR explanation) for the A 520 (30%) of the patients. After the individual ALS–patient evaluation, a total of 110 SADRs (6.35% after reviewing EMRs and 21.15% of those requiring individual patient evaluations) were identified order to identify a single SADR, we had to review the electronic records of approximately 16 patie visit 5 patients.