Adverse Drug Reactions Flashcards
Definition
any response to a drug which is noxious, unintended and occurs at doses used for prophylaxis, diagnosis or treatment
Frequency of ADR
4th leading cause of death
6.5% of all hospital admission occur as a result of ADR
10-20% of all inpatients suffer ADR
2-30% of outpatients suffer ADR
Types of classification of ADRs
Onset
Severity
Type A-F
Onset
Acute- within 60 minutes (bronchonconstriction)
Sub-acute- 1-24 hours (rash, serum sickness)
Latent- longer than 2 days (Eczematous eruptions)
Severity
Mild- bothersome but requires no change in therapy
Moderate- requires change in therapy, additional treatment, hospitalisation (amphotericin)
Severe- disabling, life threatening (kidney failure)
Type A
Augmented
Type B
Bizarre
Type C
Chronic
Type D
Delayed
Type E
End of Treatment
Type F
Failure of Treatment
Predisposing factors (5)
Multiple drugs Renal and Hepatic impairment Race and genetic polymorphisms Age (elderly and neonates) Sex- ADRs more common women
Mechanism of Type A reactions
Normal but augmented Predictable and dose dependent Due to excess pharmacological action easily reversible Most common Usually not life threatening
Mechanism of Type B ADRs
Bizarre Unpredictable Rare Cause serious illness or death Unidentified for months or year Not readily reversibly Common with macromolecules (proteins, vaccines, polypeptides)
Mechanism of Type C ADRs
Related to the duration of treatment as well as dose Does not occur with single dose Semi-predicatble Cushing's disease Steroid induced osteoporosis
Mechanism of Type D ADRs
Occur a long time after treatment
Teratogenesis: cytotoxic, Vitamin A, anti-thyroid drugs, steroids
Carcinogenesis
Mechanism of Type E ADRs
occurs suddenly after long term treatment has stopped
Unstable angina and MI when beta blockers are stopped
Alcohol
Withdrawal seizures when anti-epileptics is stopped
Mechanism of Type F ADRs
Failure of therapy
Common
Dose related
Frequently caused by drug interactions
Methods available for detection ADRs
Differential diagnosis
Medication History
Assess time of onset and dose relationship
Laboratory investigations (plasma comc. allergy test)
At risk groups of ADRs
Age Multiple medications Co-morbidity Inappropriate medication and monitoring End-organ dysfucntion Altered physiology Dose and duration Genetic predisposition
Drugs Commonly Involved
Antibiotics Antineoplastic Anticoagulants CV drugs Hypoglycaemics Antihypertensives NSAIDs/Analgesics Opiates Diagnostic agents CNS drugs
Reporting ADRs
Yellow card scheme
Online reports should me ,made for all medicines
Collect information on side effects, medical devices, defective medicine
Drug allergy
Hypersensitivity reactions
due to antigen-antibody interaction
