PHARMACOLOGY

CLASSIFICATION OF ADVERSE DRUG REACTIONS ::

As such no universal classification system for adverse reactions exists Various system used include the following 

1.Probability ::

Older systems classify adverse reactions as definite probable possible or remote reactions 

2.Body system ::

Adverse reactions may be identified by the body system as the effect (eg.hepatic toxicity renal toxicity cardiac toxicity blood toxicity etc )

3.Underlying mechanism ::

Adverse reactions may be classified as immunological and non-immunological Non -immunological include idiosyncrasy genetic renal toxicity hepatotoxicity hematological toxicology hormonal disturbances teratogenicity carcinogenicity tolerance addiction etc Immunological adverse effects include allergic reactions 

Idiosyncrasy is defined as a genetically determined abnormal reactivity to a chemical agent one of the common example is hemolytic anaemia produced by primaquine in patients with glucose -6-phosphate dehydrogenase dificiency 

            Teratogenicity is the ability of a drug to produce the  adverse effect on the foetus The importance of teratogenicity was realized after thalidomide tragedy in Europe in 1961 The drug thalidomide was introduced as a sedative and became popular specially in pregnant women Pregnant females who took the drug during pregnancy delivered babies having sealed limbs (phocomelia)

    Carcinogenicity refers to the ability of a drug to induce neoplasia or cancer for example prolonged use of estrogen may cause endometrial cancer