2. Definition
■ Adverse drug reactions (ADRs)
are unintended and harmful
events attributed to the use of
medicines.
3. FACTORS
Patient-related factors
■ Age
■ Sex
■ Genetic influence
■ Concurrent disease (renal, liver)
■ Compliance with dosing regimen
■ Total number of medications
■ Miscellaneous (diet, smoking,
environmental exposure)
Drug-related factors
■ Dose
■ Duration
■ Inherent toxicity of the agent
■ Pharmacodynamic properties
■ Pharmacokinetic properties
4. Classification of ADRs
Type of reaction
• Type A
•Type B
•Type C
•Type D
•Type E
•Type F
Onset of event
Acute (<60 minutes)
•Sub-acute (1-24 hrs)
•Latent (>2 days)
Severity
•Minor
•Moderate
•Severe
•Lethal ADRs
5. Type A or Augmented (Dose Related) ADR
Features
• Common Related to the pharmacologic action of the drug – exaggerated
pharmacologic response
• Predictable
• Low mortality
Example
•Dry mouth with Tricyclic Antidepressants
•Respiratory Depression with Opioids
• Bleeding with Warfarin
Management
•Reduce Dose or Withhold Drug
• Consider effects of concomitant therapy
6. Type B or Bizzare (Non-Dose Related) ADR
Features
•Uncommon
•Not related to the pharmacologic action of the drug
•Unpredictable
•High mortality
Example
•Immunologic reactions: anaphylaxis to penicillin
•Idiosyncratic reactions: malignant hyperthermia with general anesthetics
Management
•Withhold and avoid in future
7. Type C or Chronic (Dose Related and Time Related)
ADR
Features
•Uncommon
•Related to the cumulative dose
Example
•Hypothalamic-pituitary-adrenal axis suppression
by corticosteroids.
•Osteonecrosis of the jaw with bisphosphonates
Management
•Reduce dose or use an alternate day therapy
•withdrawal may have to be prolonged
8. Type D or Delayed (Time Related) ADR
Features
•Uncommon
•Usually dose related
•Occurs or becomes apparent sometime after use of the drug
Example
•Carcinogenesis
•Teratogenesis
•Tardive dyskinesia
•Leucopenia with lomustine
Management
•Often intractable
9. Type E or End of use (Withdrawal) ADR
Features
•Uncommon
•Occurs soon after withdrawal of the drug
Example
•Withdrawal syndrome with opiates or
benzodiazepines (e.g., insomnia, anxiety)
Management
•Reintroduce drug and withdraw slowly
10. Type F or Failure (Unexpected Failure of Therapy)
Features
•Common
•Dose related
•Often caused by drug interactions
Example
•Inadequate dosage of an oral contraceptive when used with an enzyme
inducer.
•Resistance to antimicrobial agents
Management
•Increase dosage
•Consider effects of concomitant therapy
12. Monitoring ADRs
Detecting adverse drug reaction(ADR)
Assessing causality between drug
and
Documentation of ADR
Reporting serious ADRs to
pharmacovigilance centers
13. Detection of ADRs
Pre- Marketing Studies Post– Marketing Surveillance
Spontaneous
adverse
reaction
reporting
Epidemiological
methods
Case Control
Studies
Cohort
Studies
Phase 1
Phase 2
Phase 3
14.
15. Role of Healthcare Professionals in Detecting
ADRs
■ Possibility of an ADR should always be considered during differential diagnosis.
■ ADR may be detected during ward round with the medical team.
■ Patient counselling, medication history interview and communicating with other healthcare
professional may provide additional clues.
■ Patients who are at higher risk should be monitored closely
• Patients with renal or hepatic impairment.
• Patients who had histrory of allergic reactions.
• Patients taking multiple drugs.
• Pregnant and breastfeeding women.
16. PREVENTION OF ADR
■ Avoid all inappropriate use of drug
■ Use of appropriate dose, route & frequency of drug administration
■ Elicit & take into consideration previous history of drug reactions
■ Elicit h/o allergic diseases & exercise caution
■ Rule out possibility of drug interaction
■ Adopt correct drug administration technique
■ Carry out appropriate laboratory investigation
■ Be aware of interactions with certain foods, alcohol and even with household
chemicals.
