Adverse Drug Reactions By_ Mr. Nakul Dhore ❖ Introduction & Definition ❖ Common Adverse Drug Reactions ❖ Classification Based on_ • Alphabetical • Onset of Events • Severity • Terminologies ❖ Multiple Choice Questions Pharmacy Practice Semester 7 As per B Pharm PCI Syllabus (New)

1. ADVERSE
DRUG
REACTIONS
Mr. Nakul Dhore_

2. Contents”
❖ Introduction & Definition
❖ Common Adverse Drug Reactions
❖ Classification Based on
• Alphabetical
• Onset of Events
• Severity
• Terminologies
❖ Multiple Choice Questions

3. Introduction to ADRs
DEFINITION (WHO)_ ADR is termed as any unintended/ noxious/ undesirable or unwanted
response of a drug occurred to a patient during prophylaxis, diagnosis and treatment, under
normal conditions.
E.g., Skin Rashes Nausea Blood Pressure
Abdominal pain Headache Diabetes
Vomiting Dizziness Dry Mouth
Diarrhoea Depression Cough and so on…
CLASSIFICATION_
Based On___
Alphabetics
Onset of Events
Severity
Terminological

4. Alphabetical Classification
✓ Augmented Effect
✓ Bizarre Effect
✓ Chronic Effect
✓ Delayed Effect
✓ End of Use Effect
✓ Failure of Therapy
1. Type A (AUGMENTED EFFECT)_
They are dose-dependent; predictable and non-immunologic (75-80%). The effect result
from an exaggeration of drugs normal therapeutic response when given at usual therapeutic
dose. The reactions are acute and related to mode of action.
Some predictable reactions_
Side Effect Toxic effect
Intolerances Rebound response after discontinuation
E.g., Respiratory depression is observed with opioids overdose.
Bleeding with warfarin is seen.

5. 2. Type B (BIZARRE EFFECT)_
These are Non-dose dependent, unpredictable and immunological reactions.
The reaction arises due to the presence of some peculiarities in patient. The reaction is
dependent on patient and not on drug dose. It’s a common type of reaction. Immediate
withdrawal of drug is suggested in case of serious reactions.
E.g., Drug allergy: Skin reactions, bronchospasm; vasculitis, etc.
Idiosyncrasy: Long term use of oestrogens produce cancer of uterus
Photo sensitivity: Reaction due to accumulation of drug in skin absorbing light.
Intolerance: Chloroquine causing vomiting and abdominal pain at therapeutic doses.
3. Type C (CHRONIC EFFECT)_
They are dose and time dependent adverse effect on prolonged treatment; continuous as
well. These are not pharmacologically predictable, and seen on the basis of drug properties.
The chronic reactions are related to drug concentration and are irritant in nature. They results
from continuous use of a drug.
E.g., Contact dermatitis.
Osteoporosis caused due to steroids.
Pulmonary fibrosis due to Amiodarone.

6. 4. Type D (DELAYED EFFECT)_
The effect occur long time after stopping the drug use. (late adverse effect). It appears
after many years of treatment or prolonged exposure to drug. Time related effect phenomena.
E.g., Bladder carcinoma due to cyclophosphamide.
Lymphoma due to chemotherapy
Carcinogenicity after tobacco smoking.
5. Type E (END OF USE EFFECT)_
Also called as withdrawal syndromes or effect. Occur when the drug is stopped and
termination of treatment.
E.g., Seizures on stopping phenytoin.
Rebound hypotension on stopping Clonidine.
Morphine develops withdrawal symptoms.
Type F (FAILURE OF THERAPY)_
Refers to unexpected failure of therapy. Its dose dependent often caused by drug
interactions.
E.g., Decreased clearance of drug by dialysis
Decreased effect of antibiotics due to treatment.

7. ONSET OF EVENTS
ONSET OF
EVENTS
Acute
<60 mins
Sub-acute
1-24 hrs
Latent
>2 days

8. SEVERITY
SEVERITY
Minor
Mild Therapy,
Doesn’t affect
day to day life
Moderate
Changes in Drug
Therapy &
specific
treatment
Severe
Life threatening,
Patient needs
hospitalization
Lethal
May lead to the
death of patient

9. Classification Of ADRs
Adverse Drug Reactions are classified as follows_
1) Excessive therapeutic/ pharmacological effect:
It generally appears due to over dose of a drug. This is troublesome with cardioactive
hypotensive, hypoglycaemics & CNS depressants.
E.g., Hypotensive agent when administered in excess causes profound hypotension.
Excessive therapeutic effect may also occur in patients with kidney disease (renal impairment of
greater than 70%) hypoalbuminemia; Infants & neonates. In such conditions, dose adjustment is
done in order to minimize the adverse reactions.
2) Secondary Pharmacological Effect:
The effect produced due to secondary pharmacology of drug, action produced is opposite
to the drugs therapeutic action.
E.g., Antihistamines are prescribed to allergic reactions but they also produce drowsiness due to
its CNS depressant activity simultaneously. This effect is greatly exacerbated if patient is also
taking hypnotics, cough suppressants or he/she is alcoholing.
Causing Diarrhoea with antibiotic therapy due to altered GIT’s bacterial flora.

10. 3) Idiosyncrasy:
It is genetically determined abnormal response to drug. The term idiosyncrasy is used for
unusual, unexpected effects which are unpredictable and unexplained. The reaction is restricted
to particular genotype includes drug induced foetal abnormalities.
Causes includes_ Genetic abnormality
Enzyme deficiency in body
Abnormal receptor activity
Drug interaction with unique features
E.g., Phocomelia (seal like limbs) is observed in offspring's due to exposure to thalidomide, which
produces potential teratogenicity. It causes structural changes at molecular level in foetal skeletal
and neurological tissues.
Chloramphenicol produces non dose related serious aplastic anaemia in rare individuals.
4. Allergic Reactions:
Reactions range from very mild to anaphylaxis and death rarely happens after exposure
to a wide variety of drugs. Reactions don’t resembles to expected therapeutic effects; they
reoccurs on repeated exposure to allergic drugs. Mechanism of allergic drug reaction can be
explained on immunological basis.

11. E.g., Penicillin- anaphylaxis Skin rashes- barbiturates
Leucopoenia- sulphonamide
5. Genetically determined toxicity:
It occurs in patients with special genotype or genetic makeup causing drug toxicity.
E.g., Individuals with deficiency of Glucose 6 phosphate dehydrogenase (G6PD) enzyme involved
are at more risk of developing haemolysis after use of antimalarial drugs like Primaquine, etc.
6. Toxicity following drug withdrawal:
Tolerance occurs after prolong use of drugs like narcotic, analgesics, hypnotics, ethyl
alcohol, some corticosteroids. And on sudden withdrawal of these drugs they show severe
adverse effects.
E.g., Withdrawal of CNS depressants like alcohol, barbiturates, may produce agitation,
tachycardia, confusion, etc. Clonidine on hypertension on its sudden withdrawal cause severe
hypertension.
Hereditary Conditions Drug causing toxicity
Porphyria Barbiturates
Pseudocholinesterase Succinyl choline
Slow acetylation Isoniazid, Dapsone

12. MULTIPLE CHOICE QUESTIONS
Q1. Type D is _________ type of Adverse Drug Reaction.
a) diverse b) distinct
c) dual d) delayed
Q2. Occurrence of latent type of ADR-
a) >2 days b) <2 days
c) up to 4 days d) 24 hours
Q3. Phocomelia is a/an __________ type of Reaction.
a) Allergic b) Idiosyncratic
c) Phototoxic d) All of these
Q4. Which of these type is called as withdrawal syndromes/ effect.
a) B b) A
c) E d) F
Q5. __________ADR may cause death of patient
a) Lethal b) severe
c) minor d) none of these
DABCA

13. Q6. Phocomelia is observed in offspring's due to exposure to
a) sulphonamides b) chloroquine
c) tetracycline d) None of these
Q7. Generally appears due to over dose of a drug
a) Allergic Reaction b) Idiosyncrasy
c) Excessive Effect d) Drug withdrawal
Q8. ADR is all of the following except
a) noxious b) unintended
c) desirable d) unwanted
Q9. ADR is classified on the basis of
a) alphabetics b) severity
c) onset of events d) all of these
Q10.____________enzyme involved are at more risk of developing haemolysis after use of
antimalarial drugs like Primaquine
a) CYP450 b) G6PD
c) lactose d) None of these
Q11. Steven Johnson syndrome is associated with the drug
a) Sulphonamides b) Chloramphenicol
c) Tetracyclines d) Cephalosporins DCCDBA

14. Thank You
07-12-2023