Classification and types of adverse drug reactions MCQs With Answer

Understanding the classification and types of adverse drug reactions (ADRs) is essential for B. Pharm students preparing for exams and clinical practice. This concise guide focuses on pharmacovigilance concepts, including Type A (dose-related, predictable) and Type B (non-dose-related, idiosyncratic or allergic) reactions, plus less common categories such as Types C, D, E, and F. Emphasis is on mechanisms, risk factors, prevention, reporting systems, and clinical implications of ADRs and side effects. Working through targeted MCQs reinforces recognition of causality assessment, severity grading, and management strategies. Mastery of these topics strengthens safe medication use, improves patient outcomes, and prepares students for real-world drug safety challenges. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which description best defines a Type A adverse drug reaction?

• Dose-related and predictable
• Non-dose-related and immune-mediated
• Always fatal and untreatable
• Only occurs during withdrawal

Correct Answer: Dose-related and predictable

Q2. Which feature is typical of Type B (bizarre) ADRs?

• Predictable from pharmacology
• Related to drug dose
• Idiosyncratic and unpredictable
• Always preventable with monitoring

Correct Answer: Idiosyncratic and unpredictable

Q3. Which classification lists ADRs by time course such as immediate, delayed, or late?

• Pharmacodynamic classification
• Chronological/time-related classification
• Severity grading classification
• Biochemical classification

Correct Answer: Chronological/time-related classification

Q4. Which type of ADR is illustrated by angioedema caused by penicillin?

• Dose-related pharmacological effect
• Allergic (immunologic) Type I reaction
• Cumulative toxicity due to long-term use
• Withdrawal reaction

Correct Answer: Allergic (immunologic) Type I reaction

Q5. Which is an example of a Type C (chronic) adverse drug reaction?

• Drug-induced liver injury after a single overdose
• Teratogenicity from first-trimester exposure
• Adrenal suppression after long-term corticosteroids
• Anaphylaxis immediately after injection

Correct Answer: Adrenal suppression after long-term corticosteroids

Q6. Which causality assessment tool is commonly used in pharmacovigilance?

• APGAR score
• Naranjo algorithm
• Glasgow Coma Scale
• CHA2DS2-VASc score

Correct Answer: Naranjo algorithm

Q7. Which is a major limitation of spontaneous ADR reporting systems?

• They detect all ADRs in real time
• Under-reporting of many adverse events
• They provide accurate incidence rates
• They eliminate the need for clinical trials

Correct Answer: Under-reporting of many adverse events

Q8. Which ADR category includes problems occurring on withdrawal of a drug?

• Type A
• Type D (withdrawal reactions)
• Type B
• Type F (failure of therapy)

Correct Answer: Type D (withdrawal reactions)

Q9. Which mechanism best explains Type A ADRs?

• Immune complex formation only
• Extension of the drug’s known pharmacological action
• Genetic mutation in the pathogen
• Purely psychological factors

Correct Answer: Extension of the drug’s known pharmacological action

Q10. Which is an example of a Type F ADR (failure of therapy)?

• Antibiotic-resistant infection due to inappropriate dosing
• Rash from sulfonamide allergy
• Hypoglycemia from insulin overdose
• Delayed hepatotoxicity months after exposure

Correct Answer: Antibiotic-resistant infection due to inappropriate dosing

Q11. Which pharmacogenetic factor commonly predisposes to ADRs?

• Variation in drug-metabolizing enzymes such as CYP450 polymorphisms
• Seasonal allergies unrelated to drug use
• Blood pressure variability during exercise
• Dietary preference for spicy food

Correct Answer: Variation in drug-metabolizing enzymes such as CYP450 polymorphisms

Q12. Which WHO-UMC causality category indicates a “certain” relationship?

• Unlikely
• Possible
• Certain
• Conditional

Correct Answer: Certain

Q13. Which ADR risk factor increases probability of adverse reactions?

• Polypharmacy and multiple comorbidities
• Young age with no other drugs
• Perfect renal and hepatic function
• Single short course of a topical medication

Correct Answer: Polypharmacy and multiple comorbidities

Q14. Which classification addresses severity such as mild, moderate, or severe?

• Organ/system classification
• Severity grading classification
• Therapeutic class classification
• Bioavailability classification

Correct Answer: Severity grading classification

Q15. Which ADR is best described as idiosyncratic?

• Predictable hypoglycemia from excessive insulin
• Unpredictable hemolysis in G6PD-deficient patient from primaquine
• Dose-dependent sedation from benzodiazepines
• Common gastrointestinal upset with NSAIDs

Correct Answer: Unpredictable hemolysis in G6PD-deficient patient from primaquine

Q16. Which action is essential when a severe ADR is suspected in a patient?

• Ignore and continue drug
• Discontinue suspect drug and provide supportive care
• Double the dose to overcome reaction
• Switch to another drug in the same class without evaluation

Correct Answer: Discontinue suspect drug and provide supportive care

Q17. Which drug is classically associated with Type II (cytotoxic) immune ADRs like hemolytic anemia?

• Penicillin causing immune hemolysis
• Paracetamol causing sedation
• Insulin causing hyperglycemia
• Vitamin C causing scurvy

Correct Answer: Penicillin causing immune hemolysis

Q18. Which monitoring strategy can reduce incidence of Type A ADRs?

• Therapeutic drug monitoring and dose adjustment
• Avoid reporting systems
• Randomly changing medications weekly
• Ignoring renal function in elderly

Correct Answer: Therapeutic drug monitoring and dose adjustment

Q19. Which term describes an adverse effect that is related to patient’s genetic makeup?

• Allergic reaction
• Pharmacogenetic adverse reaction
• Environmental toxicity
• Psychosomatic effect

Correct Answer: Pharmacogenetic adverse reaction

Q20. Which ADR classification includes teratogenic effects?

• Type E (end of use/teratogenicity is usually Type D but teratogenic effects are classified under Type D)
• Type A only
• Type B only
• Type X unrelated category

Correct Answer: Type E (end of use/teratogenicity is usually Type D but teratogenic effects are classified under Type D)

Q21. Which example best illustrates a Type E (end of use) ADR?

• Rebound hypertension after abrupt clonidine withdrawal
• Immediate anaphylaxis to insect venom
• Serotonin syndrome during dose adjustment
• Chronic osteomalacia from long-term drug

Correct Answer: Rebound hypertension after abrupt clonidine withdrawal

Q22. Which statement about dose-related ADRs is correct?

• They cannot be detected in clinical trials
• They are often preventable by dose adjustment
• They are always immune-mediated
• They occur only with topical drugs

Correct Answer: They are often preventable by dose adjustment

Q23. Which classification method groups ADRs according to organ system affected?

• System-organ based classification
• Time-based classification only
• Genetic classification only
• Severity grading only

Correct Answer: System-organ based classification

Q24. Which is a common example of a predictable pharmacological side effect (Type A)?

• Bleeding with anticoagulants like warfarin
• Penicillin-induced urticaria in allergic patients
• SJS from sulfonamides unrelated to dose
• Paradoxical agitation from low-dose benzodiazepines in children

Correct Answer: Bleeding with anticoagulants like warfarin

Q25. Which regulatory activity helps improve ADR detection after a drug is marketed?

• Phase IV post-marketing surveillance
• Preclinical animal testing only
• Phase I healthy volunteer trials only
• Advertising without monitoring

Correct Answer: Phase IV post-marketing surveillance

Q26. Which diagnostic sign suggests a Type I hypersensitivity ADR?

• Immediate urticaria, wheezing, hypotension after exposure
• Delayed joint pain weeks later without rash
• Isolated lab abnormality without symptoms
• Gradual hair loss over years

Correct Answer: Immediate urticaria, wheezing, hypotension after exposure

Q27. Which tool helps standardize severity grading of adverse events in clinical studies?

• Common Terminology Criteria for Adverse Events (CTCAE)
• Nutritional Risk Score
• Apnea-Hypopnea Index
• Heaviness Index

Correct Answer: Common Terminology Criteria for Adverse Events (CTCAE)

Q28. Which strategy helps prevent immune-mediated ADRs?

• Taking thorough allergy history and avoiding known allergens
• Prescribing multiple drugs without review
• Avoiding all vaccines in adults
• Ignoring past adverse reactions

Correct Answer: Taking thorough allergy history and avoiding known allergens

Q29. Which ADR is characteristic of cumulative toxicity?

• Ototoxicity with prolonged aminoglycoside therapy
• Immediate nausea after opioid injection
• Acute urticaria after first tablet
• Transient metallic taste after single dose

Correct Answer: Ototoxicity with prolonged aminoglycoside therapy

Q30. Which best describes cross-reactivity risk when substituting antibiotics?

• Structural similarity (e.g., penicillins and cephalosporins) may confer cross-reactivity
• All antibiotics are always safe alternatives
• Cross-reactivity is impossible between any beta-lactams
• Only topical antibiotics cross-react

Correct Answer: Structural similarity (e.g., penicillins and cephalosporins) may confer cross-reactivity

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com