Classification and applying pharmacovigilance principles to study adverse drug reaction and its management

Adverse drug reaction (ADR) is an unwanted, undesirable effect of medication resulting in mild to severe effect on the patient. This review explains definitions of ADR and it differentiation with adverse drug event, medication error. ADRs may cause increased length of stay or initial reason for admission and are major cause of morbidity and mortality worldwide. Risk factors for ADR occurrence include age, gender, patients with multiple diseases and multiple drug therapy (polypharmacy). ADRs are classified into different types based on the mechanism and onset of reaction. The causal relation between suspected drug and reaction can be assessed by using causality assessment scales. The severity and preventability of ADR can be assessed by severity assessment scale and preventability scale respectively. Clinical Pharmacists play an important role in monitoring and management of ADRs.