Immunology Review Corner

Immunology Review Corner: Chapter 51 of the 6th edition of Middleton’s Allergy Principles and Practice, edited by N. Franklin Adkinson, et al.

Prepared by Dr. Thao N. Tran, Puget Sound Allergy, Asthma and Immunology (formerly at Stony Brook University Hospital- SUNY), and Dr. Karla Lowe, Walter Reed Medical Center.


Chapter 51:  Antihistamines

1. Through which of the following receptors does histamine cause sensory nerve stimulation that leads to pruritus and sneezing?
a. H1
b. H2
c. H3
d. H4

2. Through which of the following receptors does histamine down-regulate the responses of type 1 and 2 helper T cells
a. H1
b. H2
c. H3
d. H4

3. Which of the following statements is true about the H1 receptor?
a. Peripheral and central H1 receptors differ from each other in structure and function.
b. H1 is a G-protein-coupled receptor.
c. The majority of H1 receptors are soluble (i.e., not membrane-bound).
d. In the vasculature, histamine has a higher affinity for H2 than H1 receptor.

4. Which of the following antihistamines is best described as lipophobic with a relatively high molecular weight?
a. Chlorpheniramine
b. Diphenhydramine
c. Loratidine
d. Dimethindene

5. H3 receptors are predominantly found in:
a. Histaminergic nerve terminals in the central nervous system, presynaptically
b. Enterochromaffin cells
c. Lymphocytes
d. Parietal cells

6. Currently available H1 antihistamines are best described as:
a. Agonists
b. Competitive antagonists
c. Inverse agonists
d. Noncompetitive inhibitors

7. Antidepressants, antipsychotics, and local anesthetics with a substituted ethylamine group are similar to H1 antihistamines in which of the following ways?
a. They all act as inverse agonists on the H1 receptor.
b. They can prevent the release of preformed mediators from mast cells and basophils.
c. They directly down-regulate the expression of adhesion proteins on epithelial cells.
d. They are not recognized by the P-glycoprotein reflux pump.

8. Which of the following is a receptor-dependent anti-inflammatory effect of H1 antihistamines?
a. Inhibition of release of preformed chemical mediators of inflammation
b. Upregulation of expression of adhesion proteins
c. Down-regulation of nuclear factor kappa B expression
d. Generation and release of superoxide radicals

9. Which of the following H1 antihistamines is dependent on transport proteins for absorption and elimination?
a. Acrivastine
b. Fexofenadine
c. Levocetirizine
d. Desloratadine

10. More than 80 percent of which of the following antihistamines is eliminated unchanged in the feces after biliary excretion?
a. Loratidine
b. Fexofenadine
c. Cetirizine
d. Azelastine

11. Which of the following statements about H1 antihistamines is true?
a. They are more effective than intranasal glucocorticoids for the relief of allergic nasal itching, sneezing, and rhinorhea.
b. They significantly shorten the duration of viral upper respiratory infections.
c. Their use in acute otitis media has been shown to significantly improve tympanic membrane compliance.
d. They are more effective than decongestants for the relief of nasal itching, sneezing, and rhinorhea.

12. Which of the following statements about antihistamine in the treatment of urticaria is correct?
a. First-generation H1 antihistamines have a better benefit-to-risk ratio than second-generation H1 antihistamines.
b. There is a relatively steep dose-response curve for H1 antihistamine in the treatment of urticaria.
c. Doxepin has greater activity at the H1 receptor than either hydroxyzine or diphenhydramine.
d. Adding an H2 antihistamine will significantly increase the adverse effects of an H1 antihistamine.

13. Which of the following antihistamines has been shown to have a topical glucocorticoid-sparing effect in atopic dermatitis?
a. Cetirizine
b. Hydroxyzine
c. Loratadine
d. Diphenhydramine

14. Which of the following antihistamines is considered a Pregnancy Category B drug by the U.S. FDA?
a. Cetirizine
b. Fexofenadine
c. Olopatadine
d. Hydroxyzine

Answers:
1. a, page 834
2. b, page 838
3. b, page 838
4. c, page 839
5. a, page 839
6. c, page 842
7. b, page 843
8. c, page 843, Box 51-1
9. b, page 845
10. b, pages 845-846
11. d, page 851
12. c, page 854
13. a, page 855
14. a, page 863