Adverse Drug Reactions

An adverse drug reaction (ADR) is an unwanted, undesirable effect of a medication that occurs during usual clinical use. Adverse drug reactions occur almost daily in health care institutions and can adversely affect a patient’s quality of life, often causing considerable morbidity and mortality. Much attention has been given to identifying the patient populations most at risk, the drugs most commonly responsible, and the potential causes of ADRs. An increase in the number of drugs on the market, an aging population, and an upward trend in polypharmacy are contributing factors to the prevalence of ADRs worldwide. Adverse drug reactions may cause patients to lose confidence in or have negative emotions toward their physicians and seek self-treatment options, which may consequently precipitate additional ADRs. Around 5% of all hospital admissions are the result of an ADR, and around 10%– 20% of inpatients will have at least one ADR during their hospital stay (Kongkaew 2008; Lundkvist 2004; Pirmohamed 1998). The actual incidence of ADRs may be even greater because some ADRs mimic natural disease states and may thus go undetected and/or unreported. Although some ADRs present as minor symptoms, others are serious and cause death in as many as 0.1%–0.3% of hospitalized patients (Lazarou 1998; Pirmohamed 1998). Adverse drug reactions should be quickly identified and managed to limit their detrimental effects on the patient. The cost of managing ADRs can be high, whether they occur in the inpatient or the outpatient setting. Because the clinical diagnosis of an ADR is not always obvious, practitioners often order additional laboratory tests or procedures to investigate the cause of a patient’s Adverse Drug Reactions