Clinical trials management system and other observational procedures work to track adverse reactions during drug development. But that's just not enough. Often adverse reactions can be identified even after successful marketing of drugs. In some cases, adverse event patterns may be identified years after the drug was launched, and products have been withdrawn from market.
Monitoring and assessing adverse reactions goes a long way in improving drug safety. Adverse Event Reporting System helps monitor adverse drug reactions and bring it to the notice of regulatory authorities and pharmaceutical companies. These are classified under different categories to make assessment of effects easier. Adverse effects are classified based on causal factors and severity.
Classification based on causal factors:
- Type A: Overdose reactions that are related to the exaggeration of the therapeutic effects of the drug. These are predictable but are often unavoidable.
- Type B: Allergic or idiosyncratic reactions, usually occurs in a minority of patients and usually unrelated to dosage. These effects are serious, unexpected and unpredictable.
- Type C: Chronic effects related to an increased frequency of 'spontaneous' disease
- Type D: Adverse reactions that are a delayed response to the drug
- Type E: The adverse effects at the end of the treatment using the particular drug
- Type F: Failed therapy
Classification based on severity:
- Permanent, persistent or significant disability
- Life-threatening condition
- Need for hospitalization
- Congenital Anomaly
- Intervention needed to prevent permanent damage
Classification of adverse reactions helps identify the cause, assess the severity and evaluate the safety of a drug. It helps drug companies and regulatory bodies analyze the relative benefits of the drug as against the adverse effects. An efficient adverse event reporting system helps identify and classify these adverse effects, thereby improving strategies for pharmacovigilance.