Adverse drug events defined

An adverse drug event (ADE) can be defined as An injury related to the use of a drug, although the causality of this relationship may not be proven (Leape 1995). Medications are the most frequent cause of adverse event. In a review it was reported that ADEs are common in most clinical settings included adult inpatients (reported incidences of 6.5%), adult outpatients (27.4%), and a paediatric inpatients (2.3%) (Morimoto et al. 2004). No data on the elderly was reported but it is probably even higher than in adult settings. 

Adverse drug events (ADEs), defined as any injury owing to a medication error, happen often. The Institute of Medicine has reported that at least 1.5 million preventable ADEs occur each year in hospitals and in people s homes. You can reduce your risk of having an ADE by having all your medications reviewed by your doctor or pharmacist. 

The terminology for describing adverse drug events can be confusing (13). An adverse drug event can be defined as any undesirable experience associated... 

Adverse events occurred in 3.7% of hospitalizations and 27.6% were due to negligence (defined as care that fell below the standard expected of physicians in that community, and which might therefore lead to legal action). Almost half of adverse (47.7%) events were associated with an operation. The most common non-operative adverse events were adverse drug events, followed by diagnostic mishaps, therapeutic mishaps, procedure related events and others. Permanent disability resulted from 6.5% of adverse events and 13.6% involved the death of a patient. Extrapolations from this data suggested that approximately 100 000 deaths each year were associated with adverse events. Later analyses indicated that 69.6% of adverse events were potentially preventable. 

A medication error is an example of a preventable cause of an adverse drug event and is defined as any preventable event that may result in incorrect medication use or patient harm while the medication is in the control of a consumer, a healfh care professional, or a patient [4,5]. Medication-related errors result in deaths or serious injuries infrequently, but a sizable number of people each year are affecfed due to the widespread use of various types of drugs bofh oufside and wifhin the hospital environments [6]. 

Advances in clinical therapeutics can result in major improvements in the health of patients. These benefits can become overshadowed by increased risks. An adverse drug event (ADE) is defined as harm experienced by a patient as a result of exposure to a medication, and ADEs account for nearly 700,000 emergency department visits and 100,000 hospitalizations each year. ADEs affect nearly 5 percent of hospitalized patients, making than one of the most common types of inpatient errors ambulatory patients may experience ADEIs at even higher rates. 

Drug-related problems can be defined as Any undesirable event experienced by the patient that involves or is suspected to involve drug therapy and that actually or potentially interferes with a desired patient outcome (Strand et al. 1990). This is a vital component of Pharmaceutical Care and Clinical Pharmacy and will be described more in detail in another chapter. It should however be noted that there are several definitions and classification systems for DRPs. A literature review (van Mil et al. 2004) identified fourteen classifications and their critical elements. In the presented definition a potential problem is a DRP but this is not the case in all definitions and classifications. This is also the case for unavoidable adverse drug reactions (e.g. with cytotoxic agents). 

Synonyms of adverse reactions generally include adverse medical effects, untoward effects, side effects, adverse drug experiences, and adverse drug reactions. Specific distinctions among some of these terms may be defined operationally. For example, the term adverse reaction is used to denote those signs and symptoms at least possibly related to a medicine, whereas the term adverse experience is used to include nonmedicine-related medical problems in a trial such as those emanating from trauma or concurrent illness. Distinctions among side effects, adverse events, and adverse reactions are illustrated in the definitions of the two former terms. 

Spontaneous adverse event reporting may be defined as any system of safety data collection which relies upon physicians, other healthcare workers and sometimes patients to report adverse clinical events which, they suspect, may be causally related to the administration of a drug or drugs. It is these systems which are sponsored by the governments of virtually all developed countries and, increasingly, by developing countries as well. For the physician in the pharmaceutical industry it is this method of safety evaluation that will most frequently be encountered and, in spite of its numerous defects and limitations, will take up much working time. 

An event is defined as a diagnosis, sign or symptom, accident, operation, change of treatment or any other incident that the doctor had considered important enough to enter into the patient s notes. For example, a fall would be considered an event, but not necessarily an adverse drug reaction. The GP is not required to decide whether events are drug related or not. 

In order to study the possible association antidepressant drugs and adverse suicidal events in adult patients, FDA planned and conducted a meta-analysis study of randomized trials of antidepressants. The meta-analysis had several key features that supported its quality and utility for regulatory actions (1) hypotheses generated from previous and independent evidence provided the meta-analysis objectives (2) the meta-analysis was based on well-defined inclusion criteria and an exhaustive set of trials with patient-level data available (3) the meta-analysis employed rigorous and consistent outcome definitions across trials and patients and (4) the meta-analysis was based on prespecified statistical analysis plan. 

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