Adverse Drug Reaction

1. Introduction to Adverse
drug
reactions
Prepared by Sudip Khan

2. Definition
 The historical development of word “pharmacovigilance” includes the Greek
word pharmacon = ‘drug’ or ‘medicinal substance and the latin word Vigilare
= ‘to keep watch,
 As per WHO, pharmacovigilance has been defined as “the since and activities
concerned with the detection, assessment, understanding and prevention of
adverse reaction to medicines.

3. Classification of ADRs
 Type A (Agumented)
 Type B (Bizarre)
 Type C (Chemical)
 Type D (Delayed)
 Type E (Exit/End of Treatment)
 Type F (Femilia)
 Type G (Genotoxicity)
 Type H ( Hypersensitivity)
 Type U (Un classified

4. Detection
1. Pre-Marketing Studies:
 The safety test of new formulated medicines is done on animal model.
 Specific animal studies for carcinogenicity, teratogenicity, and mutagenicity are easily accessible
 ADRs having frequency greater than 0.5-1.0% can be easily identified by performing clinical trails.
2. Post –marketing Surveillance:
 Spontaneous adverse drug reactions reporting are powerful and cost effective system for detecting for
unknown drug related risk.
 The two commonly used epidemiological methods are as follows:
 Cohort studies : patient exposed to a particular drug should be monitored
 Case control studies: Each case should be compared with several disease free control patients

5. Detection
3. Assessing Casualty:
 Causality assessment is a process of establishment of a relationship between a drug and a suspected
reaction.
 In case an ADR is suspected, then the assessment starts with the collection of the relevant data related
to patient’s demographics.
4. Communicating ADRs:
 At the time of basic training of health professional
 By conducting constant education programs for health Professionals
 By special designated drug information centers
5. Postal Survey Methods:
 This methods Comprise of a specific drug related questionnaire.
 It is mainly used for monitoring ADR of new drug

6. Reporting of ADRs
How To Report:
 Standardized ADR reporting form should be used for reporting
 ADRs in the reporting form should be filled appropriately in case an ADR is
encountered
 Separate forms with complete information should be used for every individual
 The completely filled ADR form should be then returned to the nearest adverse
drug reaction monitoring center or to National coordinating center
 Any follow-up information should be forwarded by another ADR form, in case of an
ADR case that has been reported already.

7. Causality Assessment
1. Expert judgment/global introspection
2. Algorithms
3. Probabilistic methods (Bayesian approaches):
Causality assessment tools are used by regulatory agencies to evaluate ADR reports. They can
help to:
 Structure the assessment of the likelihood of drug-reaction accountability
 Reduce disagreements between clinicians
 Increase ADR reporting
 Provide the relationship between the drug and events
 Detect signals

8. Severity and Seriousness Assessment
Severity is a term used to describe the intensity of a medical event. Severity assessment
categorizes adverse drug reactions (ADRs) as mild, moderate, or severe based on the steps taken for
their management.
The three criteria for assessing the severity of an ADR are:
 High severity: If it causes death or requires hospital treatment
 Moderate severity: If it requires a change in treatment management
 Mild severity: If it does not require a change in the treatment
J Seigel and PJ Schneider categorized ADRs into seven levels of severity:
 Levels 1 and 2: Less severe
 Levels 3 and 4: Moderate
 Levels 5, 6, and 7: Severe

9. Predictability and Preventability
Assesment
 Predictability and preventability assessment is a study that analyzes the
predictability and preventability of adverse drug reactions (ADRs).
 In one study, 26% of ADRs were predictable, and 27% of those were
preventable. Another study found that 40.4% of ADRs were predictable, and
18.3% were preventable.

10. Management Of ADRs
 Monitoring patient who are greater risk of Developing ADRs
 Monitoring patients who are prescribed with drugs highly likely to case ADRs
 Assessing and documenting the Patient’s previous allergic status
 Assessing patient’s Drug therapy for its appropriateness
 Replace with alternative medicines
 Use of Prophylactic regimen
 Changing Dose of the Drug
 Educating Patients