MCQ on Adverse Drug Reactions and Drug Interactions

🟢 Easy Level (1–20)

1. What is an adverse drug reaction?
   a) Intentional drug effect
   b) Drug overdose
   c) Harmful or unintended effect of a drug ✔️
   d) Therapeutic effect
   Explanation: ADRs are unwanted effects of drugs at normal doses.
2. Which organ is most commonly affected by ADRs?
   a) Skin
   b) Liver ✔️
   c) Heart
   d) Lungs
   Explanation: The liver is key in drug metabolism and susceptible to toxicity.
3. Which term describes a predictable and dose-dependent ADR?
   a) Type B
   b) Type A ✔️
   c) Type C
   d) Type D
   Explanation: Type A reactions are common and related to drug’s pharmacology.
4. Allergic reactions to drugs are classified as:
   a) Type A
   b) Type B ✔️
   c) Type C
   d) Type D
   Explanation: Type B are unpredictable and immunologic.
5. Which drug is commonly associated with anaphylaxis?
   a) Ibuprofen
   b) Paracetamol
   c) Penicillin ✔️
   d) Ranitidine
   Explanation: Penicillin allergy is a classic cause of anaphylaxis.
6. What is a drug interaction?
   a) Therapeutic effect of a drug
   b) Placebo effect
   c) Alteration of drug effect when combined with another substance ✔️
   d) Side effect
   Explanation: It occurs when one drug affects another’s activity.
7. Grapefruit juice can interfere with:
   a) Digoxin
   b) Cytochrome P450 enzymes ✔️
   c) Insulin
   d) Heparin
   Explanation: It inhibits CYP3A4, altering drug metabolism.
8. Which of the following is a common drug-drug interaction?
   a) Warfarin and aspirin ✔️
   b) Paracetamol and water
   c) Vitamin C and calcium
   d) Loratadine and ibuprofen
   Explanation: Warfarin + aspirin increases bleeding risk.
9. Which drug interaction is dangerous due to serotonin syndrome?
   a) SSRI and MAOI ✔️
   b) NSAID and antacid
   c) Beta-blocker and statin
   d) Antibiotic and analgesic
   Explanation: Both increase serotonin levels.
10. Adverse drug reactions are reported to:
    a) Hospitals only
    b) Pharmacovigilance programs ✔️
    c) Patients
    d) Pharmacies only
    Explanation: Pharmacovigilance collects and assesses ADRs.
11. What kind of ADR is teratogenicity?
    a) Type A
    b) Type B
    c) Type D ✔️
    d) Type E
    Explanation: Type D reactions are delayed, including fetal abnormalities.
12. Which drug is well known for causing ototoxicity?
    a) Paracetamol
    b) Gentamicin ✔️
    c) Loratadine
    d) Omeprazole
    Explanation: Aminoglycosides like gentamicin can damage the ear.
13. NSAIDs increase the risk of:
    a) Hyperglycemia
    b) Skin rash
    c) Gastric ulceration ✔️
    d) Tachycardia
    Explanation: They reduce protective prostaglandins in the stomach.
14. Hepatotoxicity refers to damage to the:
    a) Heart
    b) Liver ✔️
    c) Brain
    d) Lungs
    Explanation: Hepato = liver; toxicity = damage.
15. What type of interaction occurs between drug and food?
    a) Drug-drug
    b) Drug-nutrient ✔️
    c) Drug-skin
    d) Drug-environment
    Explanation: Certain foods can affect drug action.
16. Which drug is most associated with photosensitivity?
    a) Tetracycline ✔️
    b) Metformin
    c) Aspirin
    d) Atenolol
    Explanation: Tetracyclines can increase light sensitivity.
17. Which of the following is a serious ADR of clozapine?
    a) Tachycardia
    b) Vomiting
    c) Agranulocytosis ✔️
    d) Hyperglycemia
    Explanation: It can cause severe drop in WBC count.
18. Which age group is at higher risk of ADRs?
    a) 20–30
    b) 30–40
    c) Elderly ✔️
    d) Teenagers
    Explanation: Aging affects drug metabolism and clearance.
19. Polypharmacy increases risk of:
    a) Rapid healing
    b) Improved compliance
    c) Drug interactions and ADRs ✔️
    d) Drug resistance
    Explanation: More drugs = higher interaction risk.
20. Which is a common side effect of opioids?
    a) Diarrhea
    b) Constipation ✔️
    c) Hypertension
    d) Rash
    Explanation: Opioids slow GI motility.

🟡 Moderate Level (21–40)

21. Stevens-Johnson Syndrome is a rare but serious:
    a) GI side effect
    b) Skin reaction ✔️
    c) Respiratory effect
    d) Neurologic symptom
    Explanation: It is a life-threatening skin disorder.
22. Drug interactions can be:
    a) Always harmful
    b) Always beneficial
    c) Beneficial or harmful ✔️
    d) Negligible
    Explanation: Some interactions enhance efficacy, others cause harm.
23. Enzyme inducers generally:
    a) Decrease drug effectiveness ✔️
    b) Increase toxicity
    c) Slow metabolism
    d) Cause allergies
    Explanation: They speed up metabolism of co-administered drugs.
24. Enzyme inhibitors generally:
    a) Decrease drug concentration
    b) Increase drug concentration ✔️
    c) Reduce toxicity
    d) Stimulate excretion
    Explanation: They slow metabolism, raising drug levels.
25. Rifampicin is a potent:
    a) Enzyme inhibitor
    b) Enzyme inducer ✔️
    c) Antihistamine
    d) Sedative
    Explanation: It induces hepatic enzymes.
26. Which is an example of a pharmacodynamic interaction?
    a) Metabolism alteration
    b) Absorption competition
    c) Additive CNS depression by alcohol + benzodiazepine ✔️
    d) Delayed excretion
    Explanation: It affects the effect, not levels.
27. Nephrotoxicity is commonly caused by:
    a) Paracetamol
    b) Aminoglycosides ✔️
    c) Ranitidine
    d) Aspirin
    Explanation: Especially drugs like gentamicin.
28. Which drug is notorious for QT prolongation?
    a) Amoxicillin
    b) Paracetamol
    c) Azithromycin ✔️
    d) Metronidazole
    Explanation: Can increase risk of arrhythmia.
29. A delayed ADR is:
    a) Nausea
    b) Dizziness
    c) Carcinogenicity ✔️
    d) Rash
    Explanation: Cancer risk may take years to appear.
30. What is a black box warning?
    a) For expired drugs
    b) Strongest safety alert by regulatory agencies ✔️
    c) Label for generic drugs
    d) Warning on OTC drugs
    Explanation: Indicates serious/life-threatening risks.
31. Idiosyncratic reactions are:
    a) Predictable
    b) Dose-dependent
    c) Unpredictable and rare ✔️
    d) Always mild
    Explanation: Not explained by drug’s usual pharmacology.
32. Which system is most commonly used to classify ADRs?
    a) WHO-Uppsala Monitoring
    b) Rawlins and Thompson ✔️
    c) IUPAC
    d) CDC classification
    Explanation: Type A–F classification.
33. Type E reaction refers to:
    a) Immune response
    b) Teratogenicity
    c) End of treatment effects ✔️
    d) Carcinogenicity
    Explanation: Seen during drug withdrawal.
34. Cimetidine can cause interaction by:
    a) Inhibiting cytochrome P450 ✔️
    b) Inducing renal enzymes
    c) Binding calcium
    d) Enhancing GABA
    Explanation: It increases levels of other drugs.
35. ADRs can be minimized by:
    a) Increasing dose
    b) Monitoring therapy ✔️
    c) Ignoring symptoms
    d) Self-medication
    Explanation: Monitoring ensures safety.
36. Drug interaction may result in:
    a) Increased efficacy
    b) Decreased efficacy
    c) Adverse effects
    d) All of the above ✔️
    Explanation: Interactions have various outcomes.
37. Thiazide diuretics can interact with:
    a) Paracetamol
    b) Lithium ✔️
    c) Ranitidine
    d) Loratadine
    Explanation: Increase lithium levels and toxicity.
38. Which class of drugs interacts with dairy?
    a) NSAIDs
    b) Tetracyclines ✔️
    c) Beta-blockers
    d) Antihistamines
    Explanation: Calcium binds tetracycline, reducing absorption.
39. Concomitant use of ACE inhibitors and potassium-sparing diuretics may cause:
    a) Hyperkalemia ✔️
    b) Hypokalemia
    c) Hypertension
    d) Renal stones
    Explanation: Both retain potassium.
40. Chronic NSAID use with corticosteroids increases risk of:
    a) Hypoglycemia
    b) GI bleeding ✔️
    c) Seizures
    d) Fever
    Explanation: Both damage gastric mucosa.

🔴 Hard Level (41–50)

41. Drug-induced lupus is associated with:
    a) Hydralazine ✔️
    b) Ranitidine
    c) Omeprazole
    d) Aspirin
    Explanation: Hydralazine and procainamide may cause lupus-like syndrome.
42. Which ADR is caused by long-term phenytoin use?
    a) Hair loss
    b) Gingival hyperplasia ✔️
    c) Rash
    d) Hypertension
    Explanation: Overgrowth of gums is a known effect.
43. CYP3A4 is involved in the metabolism of:
    a) Many drugs ✔️
    b) Only antivirals
    c) Only antibiotics
    d) None of the above
    Explanation: A major metabolic enzyme.
44. Rifampicin reduces the effect of:
    a) Oral contraceptives ✔️
    b) Paracetamol
    c) Ibuprofen
    d) Amoxicillin
    Explanation: Induces metabolism leading to contraceptive failure.
45. Red-man syndrome is caused by:
    a) Metformin
    b) Vancomycin ✔️
    c) Doxycycline
    d) Clindamycin
    Explanation: Caused by rapid infusion of vancomycin.
46. Disulfiram-like reaction is caused by:
    a) Amoxicillin
    b) Ibuprofen
    c) Metronidazole with alcohol ✔️
    d) Digoxin
    Explanation: Leads to flushing, nausea with alcohol.
47. Linezolid + SSRI may lead to:
    a) Hypotension
    b) Serotonin syndrome ✔️
    c) Constipation
    d) Bradycardia
    Explanation: Both increase serotonin.
48. What is the outcome of aspirin + methotrexate?
    a) Methotrexate toxicity ✔️
    b) Enhanced analgesia
    c) Faster excretion
    d) Liver protection
    Explanation: Aspirin reduces clearance of methotrexate.
49. Which supplement reduces levodopa efficacy?
    a) Vitamin B6 ✔️
    b) Iron
    c) Vitamin C
    d) Calcium
    Explanation: Pyridoxine increases peripheral metabolism of levodopa.
50. A serious ADR reported with fluoroquinolones:
    a) Tinnitus
    b) Tendon rupture ✔️
    c) Constipation
    d) Hyperglycemia
    Explanation: Fluoroquinolones can damage tendons.