1. Pharmacovigilance (PV)

2. Pharmacovigilance (PV)
PV is concerned with detection, assessment & prevention of adverse reactions to drugs (ADRs) or any drug-related problems 2 2

3. Drug-Related Problems
Lack of efficacy.
Manufacturing defects.
Medication errors.
Drug misuse and abuse.
Overdose.
Contamination.
Counterfeit products. 3

4. Recently, the concerns of PV have been widened to include:
Herbal
Traditional and complementary medicines
Blood products
Biologicals
Medical devices
Vaccines 4

5. Why Pharmacovigilance?
The root of pharmacovigilance:
Pharmaco (Greek)= Drug
Vigilance (Latin)= to keep awake or alert
Because information collected during pre-marketing phase are incomplete with regard to possible ADR
Tests in animals are insufficiently predictive of human safety

6. Why Pharmacovigilance?
In clinical trials:
Patients are limited in number
Conditions of use differ from those in clinical practice
Duration of trials is limited 6

7. Why Pharmacovigilance?
Information about rare adverse reactions, chronic toxicity, use in special groups (children, elderly or pregnant women) or drug interactions is often incomplete or not available
Post-marketing surveillance by companies is therefore essential

8. Pre-marketing clinical trials do not have :
Why Pharmacoviglance?
Pre-marketing clinical trials do not have :
Statistical power to detect rare ADRs
To identify delayed ADRs
To identify effects from long-term exposure
PV plays a prominent role in establishing safety profile of marketed drugs 8 8

9. 9

10. Definition of ADR
An ADR is defined according to definition of WHO “any response to a drug which is noxious, unintended & that occurs at doses used in man for prophylaxis, diagnosis, or therapy of diseases’’ 10

11. Epidemiology of ADRs
ADRs represent a significant cause of morbidity & mortality
Many ADRs are mild, sometimes serious & can cause death
U.S, ADRs caused deaths per year, 4th & 6th leading cause of death
About 50% of ADRs are preventable 11 11

12. Importance of ADRs Prolong length of stay in hospitals
Increase costs of patient care
Commonest cause of drug withdrawal from market:
Reductil (Sibutramine)
Valdecoxib (Bextra)
Rofecoxib (Vioxx) 12

13. ADRs is considered serious if:
Causes death of patient
Life-threatening
Prolong inpatient hospitalisation
Causes significant or persist disability
Congenital abnormality 13

14. Risk Factors predisposing to ADRs
Age
Long duration of treatment
Polypharmacy
Liver, kidney diseases

15. Causes of ADRs
Patient
Drug
Prescriber
Environmental factors

16. Causes of ADRs - Narrow therapeutic index, e.g. warfarin, digoxin
2. The drug
- Narrow therapeutic index, e.g. warfarin, digoxin
- Antimicrobials have a tendency to cause allergy
- Ingredients of a formulation, e.g. colouring, flavouring 16 16

17. Drugs most commonly causing ADRs
Anticancer drugs
Immunomodulators
Analgescis
Warfarin
Diuretics
Digoxin
Antibacterials
Steroids
Antihypertensives

18. Why report suspected ADRs?
Documentation of ADRs in patients’ records is often poor
Physicians fear that reporting of ADR may put them at risk
Under-reporting is common phenomenon 18

19. Reporting Methods Spontaneous reporting: (Voluntary)
Doctors, nurses & pharmacists are supplied with forms to record suspected ADRs
Reporting ADRs to National Pharmacovigilance Centre
In UK, this is called ‘Yellow Card system’

20. Prevention of ADRs Taking a drug history
Reduce number of prescribed drugs
Remembering that certain patients
(elderly, those with liver or renal diseases) more susceptible to ADRs