ADVERSE DRUG REACTIONS: AN OVERVIEW OF THE OLD AND CONTINUOUS CHALLENGE TO DRUG THERAPY AND DEVELOPMENT

الملخص

Adverse drug reactions (ADRs) represent a major health problem worldwide and constitute a big challenge
to drug therapy and the drug development process. ADRs are responsible for 3% of total hospital admissions and occur in 10 to 20% of hospitalized patients. It has been estimated that ADRs account for at least 100,000 deaths annually in the United States alone ranking them as the fifth leading cause of death. According to the World Health Organization definition an ADR is a noxious and unintended response to a drug that occurs at a dose normally used in man for prophylaxis, diagnosis or therapy. This commonly used definition, however, excludes other drug therapy consequences such as drug abuse, accidental and inadvertent drug overdose and therapeutic failure. ADRs are classified into two main groups: Type A, which are predictable from the drugs’ normal pharmacological actions and are dose dependent and Type B, which are unpredictable, unrelated to the drugs’ pharmacology and do not have clear dose dependency. This is an overview of the currently used definitions and classifications of ADRs in clinical pharmacology and toxicology. Specific relevant examples are cited and some important points are discussed in the light of current knowledge. A special emphasis is made on the importance of ADRs in clinical drug therapy and drug development, which are the areas where ADRs play the most significant role.