📌 Introduction
Antihistamines are widely used in the treatment of allergic conditions and are an important topic in pharmacology exams like GPAT, DSSSB, and other pharmacy tests. These MCQs will help you revise classification, mechanism, uses, and side effects quickly.
📝 MCQs on Antihistamines
1. Antihistamines block which receptor?
A) H2
B) H1
C) Dopamine
D) Serotonin
✔ Answer: B) H1
➜ Explanation: They block H1 receptors to reduce allergic reactions.
2. Histamine is released during:
A) Digestion
B) Allergy
C) Sleep
D) Exercise
✔ Answer: B) Allergy
3. First-generation antihistamines cause:
A) Alertness
B) Sedation
C) Hypertension
D) Weight loss
✔ Answer: B) Sedation
4. Which is a first-generation antihistamine?
A) Cetirizine
B) Loratadine
C) Diphenhydramine
D) Fexofenadine
✔ Answer: C) Diphenhydramine
5. Which is second-generation antihistamine?
A) Promethazine
B) Chlorpheniramine
C) Cetirizine
D) Diphenhydramine
✔ Answer: C) Cetirizine
6. Second-generation drugs cause:
A) More sedation
B) Less sedation
C) Kidney damage
D) Liver failure
✔ Answer: B) Less sedation
7. Antihistamines are used in:
A) Diabetes
B) Allergy
C) Cancer
D) Hypertension
✔ Answer: B) Allergy
8. Motion sickness is treated by:
A) NSAIDs
B) Antibiotics
C) Antihistamines
D) Antacids
✔ Answer: C) Antihistamines
9. Which drug is sedative?
A) Loratadine
B) Fexofenadine
C) Diphenhydramine
D) Cetirizine
✔ Answer: C) Diphenhydramine
10. Antihistamines act by:
A) Increasing histamine
B) Blocking histamine
C) Destroying bacteria
D) Increasing insulin
✔ Answer: B) Blocking histamine
11. Histamine causes:
A) Sleep
B) Allergy symptoms
C) Growth
D) Digestion
✔ Answer: B) Allergy symptoms
12. Which crosses BBB?
A) Second gen
B) First gen
C) Antibiotics
D) NSAIDs
✔ Answer: B) First gen
13. Which is non-sedating?
A) Diphenhydramine
B) Promethazine
C) Loratadine
D) Chlorpheniramine
✔ Answer: C) Loratadine
14. Antihistamines reduce:
A) Blood sugar
B) Allergy
C) Oxygen
D) Insulin
✔ Answer: B) Allergy
15. Side effect of first gen:
A) Sedation
B) Energy
C) Growth
D) Appetite
✔ Answer: A) Sedation
16. Dry mouth is due to:
A) Anticholinergic effect
B) Insulin
C) Hormones
D) Enzymes
✔ Answer: A) Anticholinergic effect
17. Which drug is used in urticaria?
A) Cetirizine
B) Insulin
C) Aspirin
D) Penicillin
✔ Answer: A) Cetirizine
18. Promethazine is:
A) Antibiotic
B) Antihistamine
C) NSAID
D) Antacid
✔ Answer: B) Antihistamine
19. Second-generation drugs have:
A) High sedation
B) Low sedation
C) No effect
D) Toxicity
✔ Answer: B) Low sedation
20. Antihistamines are contraindicated in:
A) Allergy
B) Glaucoma
C) Fever
D) Pain
✔ Answer: B) Glaucoma
21. Which is used in common cold?
A) Antibiotics
B) Antihistamines
C) Insulin
D) Steroids
✔ Answer: B) Antihistamines
22. Which effect is anti-pruritic?
A) Pain relief
B) Itching relief
C) Fever
D) Sleep
✔ Answer: B) Itching relief
23. H1 receptor is responsible for:
A) Acid secretion
B) Allergy
C) Insulin
D) Growth
✔ Answer: B) Allergy
24. Which is safest (less sedative)?
A) Diphenhydramine
B) Promethazine
C) Fexofenadine
D) Chlorpheniramine
✔ Answer: C) Fexofenadine
25. Which is used for insomnia?
A) Loratadine
B) Cetirizine
C) Diphenhydramine
D) Fexofenadine
✔ Answer: C) Diphenhydramine
26. Antihistamines may cause:
A) Dry mouth
B) Growth
C) Energy
D) Weight loss
✔ Answer: A) Dry mouth
27. Which generation crosses BBB?
A) First
B) Second
C) Third
D) None
✔ Answer: A) First
28. Which is long-acting?
A) First gen
B) Second gen
C) NSAIDs
D) Antibiotics
✔ Answer: B) Second gen
29. Antihistamines block:
A) Enzymes
B) Hormones
C) Receptors
D) DNA
✔ Answer: C) Receptors
30. Best use of antihistamines:
A) Infection
B) Allergy
C) Diabetes
D) Cancer
✔ Answer: B) Allergy
🎯 Conclusion
These 30 MCQs on antihistamines will help you revise key pharmacology concepts and improve your exam performance. Practice regularly for best results.
👉 Read full notes here: https://pharmacymcq.in/antihistamines-classification-mechanism-uses-side-effects/