Adverse Drug Reactions: An Overview (original) (raw)

Drug is single active chemical entity present in a medicine that is used for diagnosis, prevention and treatment of diseases. Adverse drug reaction is unexpected effect of drug on animal and human being and considered as one of causes of morbidity and mortality of hospitalized patients. Although many drug reactions are preventable such as those associated with prescription errors while others are not preventable. The adverse drug reactions are often not discovered until after the drug has been marketed. The occurrence of ADR can be explain on basis of the drug's pharmacology and show apparent dose-response relationship in susceptible animal and human being. Adverse drug reactions caused by immune and non-immune mechanisms are a major cause of morbidity and mortality worldwide. They are the most common iatrogenic illness, complicating 5% to 15% of therapeutic drug courses. Adverse drug reactions can be divided schematically into two major categories: type A and type B. Type A reactions are common, predictable and may occur in any individual. Type B ADRs are uncommon and unpredictable and only occur in susceptible individuals. A critical factor in the drug response such as in ADRs could be the inter-patient differences in plasma concentrations arising from the same drug regimen. Pharmacogenomics is likely to be particularly useful for drugs that have variable kinetics and dynamics, and narrow therapeutic index. Management strategies employed for the ADRs is categorized as drug withdrawal, dose reduction, additional treatment for ADR, and no change in regimen with no additional treatment. Managing these cases should be done immediately after their appearance and those individuals or animals with the problem should be carefully handled with the appropriate medical expertise. Better approaches must be devised for reporting and assessing ADR. In addition, pharmaceutical companies should strive to reduce the adverse effect of a drug. INTRODUCTION Drug is single active chemical entity present in a medicine that is use for diagnosis, prevention and treatment of diseases. (Mererjone, 2003). The person-to-person variability of drug response is a major problem in clinical practice and drug development (Meyer, 2000). It can lead to therapeutic failure or adverse effects of drugs (ADRs) in individuals or subpopulations of patients. Adverse drug reaction is unexpected effect of drug on animal and human being and considered as one of causes of morbidity and mortality of hospitalized patients (Ditto, 2004). A productive hospital-based reporting program can be instrumental in providing valuable information regarding potential problems of drug usage in an institution. Through these efforts, problems are identified and resolved, which results in continuous improvement inpatient Care (Murphy and Frigo, 1993). Spontaneous reporting program, a common method of drug surveillance is capable of recognizing ADRs in the daily medical practice even though under reporting and absence of information on number of people actually exposed to the drug are its disadvantages (Alvarez-Requejo et al., 1998). Although many drug reactions are preventable such as those associated with prescription errors while others are not preventable. The adverse drug reactions are often not discovered until after the drug has been marketed. Pharmaceutical companies strive to work out the adverse effect profile of a drug before it is marketed, but because the complete range of adverse effects is not known, therefore, most severe drug induced reactions cannot be elucidated before licensing, therefore efficient post marketing surveillance is needed. However, even if improved surveillance is carried out the problem will not be resolved. As more drugs are marketed and as more individuals take multiple drugs, the occurrence of adverse drug reactions will probably continue to increase. Adverse drug reaction are still considered as problem of drug therapy in association with considerable morbidity, mortality, decrease compliance and therapeutic success as well as high direct and indirect medical cost (Tripathis,2003). There for the objectives of this seminar paper are: to high light the causality, clinical manifestation and management of ADR, and to recommend further study in the area of ADR.