The document defines adverse drug reactions (ADRs) as any unwanted or harmful effects from a drug taken at normal doses for treatment or diagnosis of disease. ADRs can be caused by the dose, allergic reactions, or idiosyncratic reactions in individual patients. There are two major types - augmented reactions which are common and based on pharmacological properties, and bizarre reactions which are less common and require drug withdrawal. Diagnosis involves considering rechallenge or reporting to MedWatch. ADRs refer to causal harmful effects, while adverse drug events (ADEs) refer to any unfavorable medical occurrence during drug treatment whether or not causality is established, and can include medical errors.

1. ADVERSE
DRUG
REACTIONS
Dr.Ajith JS
Asst.Professor
Dept of Pharmacology

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Definition:
Adverse drug reaction (ADR)—The World Health Organization defines an
ADR as “any response to a drug which is noxious and unintended, and
which occurs at doses normally used in man for prophylaxis, diagnosis,
or therapy of disease, or for the modification of physiological function.”

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• Adverse drug reaction (ADR, or adverse drug effect) is a broad term
referring to unwanted, uncomfortable, or dangerous effects that a drug
may have.

4. Causes of ADRs
 Dose-related ADRs
 Allergic ADRs
 Idiosyncratic ADRs
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5. 2 Major types of ADR
 Augmented/Predicted ADR– Based on the pharmacological properties of a
drug. It is a more common type of ADR. This type of ADR is mostly
preventable and reversible.
 Bizarre/Unpredictable ADR- Based on the peculiarities of a patient. It is a
less common type of ADR. This type of ADR is more serious and requires
drug withdrawal. It includes hypersensitivity/allergy, Idiosyncrasy.
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7. Diagnosis of Adverse Drug Reactions
 Consideration of rechallenge
 Reporting of suspected ADRs to MedWatch
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8. Difference Between ADR and ADE
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ADR which is called the adverse drug reactions is any retaliation to a drug that
is harmful, toxic, and unplanned that occurs at doses and used in human’s
diagnosis or therapy for a disease excluding failure to achieve the intended
purpose. ADR is a conceptual and practically orthodox drug.
ADE which is called the adverse drug event is an unfavourable drug event that
tells the injuries resulting from the use of the drug. It includes the harm caused
by drug and harmful reactions from the use of the drug. A causal association is
not found between the drug and the event.

10. Parameter of Comparison ADR ADE
Concept
Any toxic and harmful change
which is suspected to be due to a
drug normally used in man and
occurs at doses.
Any medical occurrence which is
not expected, but present during
treatment with a pharmaceutical
product.
Causal Relationship
A causal connection between the
drug and the event is suspected.
No need to have a Causal
relationship.
Medical Errors
Medical errors are not included in
the definition.
Medical errors are included in the
definition.
Common Example
An allergic reaction from
medication.
Aspiration pneumonia after over-
sedation secondary to morphine
overdose.
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