Adverse drug reactions defined

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). 

An adverse drug reaction is defined by WHO as A response to a dmg which is noxious and unintended, and which occurs at doses normally used in man for the prophylaxis, diagnosis, or therapy of disease, or for the modification of physiological... 

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. 

Types of adverse drug reaction There are several classifications of adverse reactions, but the most commonly employed define two principal kinds (A and B) and three subordinate classes (C, D and E). 

Adverse drug reaction may be defined as any response to a drug which is noxious (injurious) and unintended, and which occurs at doses of an appropriately given drug used in man for prophylaxis, diagnosis or therapy excluding therapeutic failures. ... 

A most crucial term to be defined is risk. The terms of its description should include, first, the patient s response to the study drug in comparison to response to control therapy or other alternative forms of treatment or no treatment at all and, second, the acceptability and duration of drug-free pretreatment periods, placebo controls, potential adverse drug reactions, and duration of exposure. 

Adverse drug reaction (ADR) is defined in the law. The person authorised for the drug prescription, wholesale, dispensation and manufacture is obliged to report an ADR to the SIDC. The SIDC has the right to postpone or withdraw the medicinal products or medical device from the market. 

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. 

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