This document discusses different classifications of adverse drug reactions (ADRs). The traditional classification divides ADRs into type A reactions, which are dose-dependent and predictable, and type B reactions, which are not dose-dependent and are unpredictable. Later classifications include type C-E reactions by Rowlins and Thompson based on chronicity, delay of onset, and end of drug use. The DoTS classification by Aronson and Ferner in 2000 categorizes ADRs based on dose, time course, and patient susceptibility. It provides examples of ADRs like corticosteroid-induced osteoporosis and penicillin anaphylaxis. The DoTS classification is gaining acceptance as it better accounts for ADRs

1. Adverse Drug Reaction
-Classification
Dr. Ajith JS
Asst. Professor
Department of Pharmacology
Sanjivani College of Pharmaceutical Education & Research, Kopargaon

2. Traditional Classification
2
- 1970s
ADR
Type B
(Bizarre)
Type A
(Augmented)

3. 3
TYPE A (Augmented) TYPE B (Bizarre)
Dose – related Non dose – related
Predictable Unpredictable
Common Uncommon
Normally reversible Maybe serious / irreversible
Manageable with dosage adjustment Drug discontinuation needed
Eg. Warfarin - Bleeding Eg. Beta blockers - Bronchospasm
Traditional Classification

4. - Rowlins and Thompson
4
Type Name Example
Type C Chronic Corticosteroid – adrenal suppression
Type D Delayed Neuroleptics – Tardive dyskinesia
Type E End of use Opiates – Withdrawal syndrome
Type F Failure of therapy Decreased effect due to antibiotic resistance

5. DoTS Classification
5
DoTS
Susceptibility
Time course
Dose relatedness
- Aronson & Ferner – 200

6. DoTS Classification
6
Dose
Toxic
ADRs that are
generally
observed with
drug levels that
are too high
Collateral
ADRs that can
happen in usual
therapeutic
range
Hyper
susceptibility
ADRs that can
even occur in
low,
subtherapeutic
doses

7. 7
DoTS Classification
Time
Dependant
Independent:
NSAIDs –
Renal Failure
Early: nitrate
induced headache
Intermediate: Type
II, III, IV
hypersensitivity
Late: Antipsychotics
– tardive dyskinesia
Delayed:
Cancer
Withdrawal:
Opiates –
withdrawal
syndrome
First dose:
Penicillin
anaphylaxis
Rapid
administration:
Vancomycin –
red man
syndrome

8. 8
DoTS Classification
Susceptibility
Gender:
-Females are
more prone to
ADRs
Age:
- Elderly and
pediatrics
-Elderly patients
are more
sensitive to
antipsychotics
and anxiolytics
Ethnic origin:
G6PD deficiency
High risk of
hemolysis with
nitrofurantoin or
quinolone
antibtiotics
Genetics:
CYP2C9
polymorphisms -
bleeding
Disease:
Hepatic or renal
disease – kinetics
is altered

9. Examples:
1. Corticosteroids – Osteoporosis
Dose – Collateral
Time - Late
Susceptibility – Age & sex
2. Anaphylaxis of penicillin
Dose: hypersensitivity
Time – First dose
Susceptibility – requires previous sensitization
9

10. DoTS Classification
10
 Gaining acceptance
 ADRs do not clearly fit in the traditional classification
 Provides pointers on how specific ARDs can be avoided