Definition: Adverse drug reactions refer to any unexpected, undesired or excessive response to a
medicine or a drug for diagnosis and therapy of a disease.
These reactions can start soon after the intake of medicine or up to two weeks after
stopping the medicine.
They can lead to serious conditions such as anaphylaxis reactions (Whole body ex:
Fainting, dizziness, flushing, Respirotory ex: Rapid or short breathing, Skin ex: Swelling
under the skin, blue skin due to lack blood circulation, GIT ex: Nausea, vomiting, Commonly
ex: Fast heart rate, tongue swelling, difficulty in swallowing, mental confusion, nasal
congestion) and it is estimated that they account for 15% of all hospital admissions.
FACTORS INFLUENCING ADR’S:
Factors influencing adverse drug reactions are
a) Poly pharmacies: The incidence of ADR’S increase with number of drugs given due to the
risk of interactions.
b) Age: The incidence of ADR’s is more in young and very old people due to poorly
developed and altered psychological functions.
c) Multiple and incurrent diseases: Multiple and incurrent diseases can alter the Pharmaco
kinetic characters of the drugs at tissue levels.
d) Drug characteristics: They can alter absorption, metabolism, and elimination process of
e) Gender: Several studies have shown that women for some drugs suffer more than men due
to sex related characters in kinetics and dynamics.
f) Race: These are genetically determined responses in populations.
MANAGEMENT OF ADR’S:
1) Monitoring the patients who are at greater risk of developing ADR’S.
2) Monitoring the patients who are prescribed with drugs that are highly susceptible to cause
3) Assessing and documenting the patient’s previous allergic status.
4) Assessing the patient’s drug therapy for its appropriateness.
5) Assessing possible drug interactions in case of multiple therapies.
6) Assessing health care professionals in detection and assessment of ADR’S.
7) Encouraging healthcare professionals in reporting on ADR’S.
8) Documentation of suspected, reported reactions for future reference.
9) Follow up of patients to assess the outcome of reaction and management.
10) Obtain feedback about reported reaction.
11) Educating healthcare professionals about the importance of ADR’S.
12) Patient education.
classification of ADR with example
Type of reaction:
Type A: Augmented pharmacological effect
feature: common predictable effect dose-dependent low mobility low mortality Ex: bradycardia associated with a beta adrenergic receptor antagonist.
Type B: Bizarre effect not related to pharmacological effect
Features; uncommon unpredictable not dose-dependent high mobility high mortality. Ex:anaphylaxis associated with penicillin antibiotic.
Type C: dose related and time related
feature: uncommon related to the cumulative dose Ex: hypothalamic pituitary adrenalaxis suppression by corticosteroids.
Type D: time related
feature: uncommon and usually dose related occurs or become apparent some time after use of the drug Ex: Carcinogenesis
Type E: withdrawal
Features: uncommon occurs soon after withdrawal of drug Ex: Opiate withdrawal syndrome
Type F: unexpected failure of therapy
Features: common dose related often caused by drug interaction Ex: failure of oral contraceptive in presence of enzyme inducer.
Factors affecting susceptibility to adverse drug reaction awareness of the factors which increase the the risk of adverse drug reaction is key to reducing the burden on individual patient by informing prescribing decisions.
The risk that drug dose to patients various dependent on the population exposed and the individual characteristic of patients
Age: children differ from adults in their response to drugs neonatal differences in body composition metabolism and other physiological parameters can increase the risk of specific adverse reaction.
Higher body water content can increase the volume of distribution for water soluble drugs reduces albumin and total protein results in higher concentration of highly protein bound drugs.
Women may be more susceptible to adverse drug reaction.
In addition there are particular adverse drug reaction that appear to be more common in women than men.
Ex: Impairment of concentration and psychiatric adverse events events associated with the antimalarial mefloquine are more common in female.