Chapter 189 - Antihistamines

Question 1

TABLE 189-1
Basic Pharmacology of Antihistamines

Fill in the blanks

_____ antihistamines are _____ agonists that reversibly bind and stabilize the inactive form of the histamine receptor, thereby favoring the inactive state.

Answer 1

Both H1 and H2 antihistamines are inverse agonists that reversibly bind and stabilize the inactive form of the histamine receptor, thereby favoring the inactive state.

Question 2

TABLE 189-1
Basic Pharmacology of Antihistamines

Fill in the blanks

_____ agents are relatively lipophilic, which enhances penetration of the blood–brain barrier and leads to sedation.

Answer 2

First-generation H1 agents are relatively lipophilic, which enhances penetration of the blood–brain barrier and leads to sedation.

Question 3

TABLE 189-1
Basic Pharmacology of Antihistamines

Fill in the blanks

_____ antihistamines may interact with other drugs metabolized by the hepatic cytochrome P450 system leading to drug–drug interactions.

Answer 3

First-generation H1 antihistamines may interact with other drugs metabolized by the hepatic cytochrome P450 system leading to drug–drug interactions.

Question 4

TABLE 189-1
Basic Pharmacology of Antihistamines

Fill in the blanks

_____ antihistamines have poor penetration of the blood–brain barrier and thus are less sedating.

Answer 4

Second-generation H1 antihistamines have poor penetration of the blood–brain barrier and thus are less sedating.

Question 5

TABLE 189-1
Basic Pharmacology of Antihistamines

Fill in the blanks

_____ antihistamines bind selectively to peripheral H1 receptors and have fewer CNS effects.

Answer 5

Second-generation H1 antihistamines bind selectively to peripheral H1 receptors and have fewer CNS effects.

Question 6

TABLE 189-1
Basic Pharmacology of Antihistamines

Fill in the blanks

_____ antihistamines require less hepatic metabolism and thus are less likely to interact with other medications.

Answer 6

Second-generation H1 antihistamines require less hepatic metabolism and thus are less likely to interact with other medications.

Question 7

TABLE 189-1
Basic Pharmacology of Antihistamines

Fill in the blanks

There is no evidence of _____ or _____ to first-generation or second-generation antihistamines.

Answer 7

There is no evidence of tolerance or tachyphylaxis to first-generation or second-generation antihistamines.

Question 8

TABLE 189-2 vs TABLE 189-6
Indications for Treatment with H1 Antihistamines vs Dermatologic Indications for Treatment with H2 Antihistamines

Acute urticaria

Answer 8

H1 Antihistamines

Question 9

TABLE 189-2 vs TABLE 189-6
Indications for Treatment with H1 Antihistamines vs Dermatologic Indications for Treatment with H2 Antihistamines

Chronic idiopathic urticarial

Answer 9

H1 Antihistamines

Question 10

TABLE 189-2 vs TABLE 189-6
Indications for Treatment with H1 Antihistamines vs Dermatologic Indications for Treatment with H2 Antihistamines

Physical urticarias and dermatographism

Answer 10

H1 Antihistamines

Question 11

TABLE 189-2 vs TABLE 189-6
Indications for Treatment with H1 Antihistamines vs Dermatologic Indications for Treatment with H2 Antihistamines

Pruritus associated with histamine release

Answer 11

H1 Antihistamines

Question 12

TABLE 189-2 vs TABLE 189-6
Indications for Treatment with H1 Antihistamines vs Dermatologic Indications for Treatment with H2 Antihistamines

Symptoms of mastocytosis

Answer 12

H1 Antihistamines

Question 13

TABLE 189-2 vs TABLE 189-6
Indications for Treatment with H1 Antihistamines vs Dermatologic Indications for Treatment with H2 Antihistamines

Acute allergic reactions

Answer 13

H2 Antihistamines

Question 14

TABLE 189-2 vs TABLE 189-6
Indications for Treatment with H1 Antihistamines vs Dermatologic Indications for Treatment with H2 Antihistamines

Chronic urticaria (as a second-line agent)

Answer 14

H2 Antihistamines

Question 15

TABLE 189-2 vs TABLE 189-6
Indications for Treatment with H1 Antihistamines vs Dermatologic Indications for Treatment with H2 Antihistamines

Systemic symptoms associated with mastocytosis (especially GI related)

Answer 15

H2 Antihistamines

Question 16

TABLE 189-3
Dosing Regimens for H1 Antihistamines

CONDITIONS REQUIRING
DOSAGE ADJUSTMENT
Hepatic vs Renal vs Both

Chlorpheniramine

Answer 16

Hepatic impairment

Question 17

TABLE 189-3
Dosing Regimens for H1 Antihistamines

CONDITIONS REQUIRING
DOSAGE ADJUSTMENT
Hepatic vs Renal vs Both

Cyproheptadine

Answer 17

Hepatic impairment

Question 18

TABLE 189-3
Dosing Regimens for H1 Antihistamines

CONDITIONS REQUIRING
DOSAGE ADJUSTMENT
Hepatic vs Renal vs Both

Diphenhydramine

Answer 18

Hepatic impairment

Question 19

TABLE 189-3
Dosing Regimens for H1 Antihistamines

CONDITIONS REQUIRING
DOSAGE ADJUSTMENT
Hepatic vs Renal vs Both

Hydroxyzine

Answer 19

Hepatic impairment

Question 20

TABLE 189-3
Dosing Regimens for H1 Antihistamines

CONDITIONS REQUIRING
DOSAGE ADJUSTMENT
Hepatic vs Renal vs Both

Tripelennamine

Answer 20

Hepatic impairment

Question 21

TABLE 189-3
Dosing Regimens for H1 Antihistamines

CONDITIONS REQUIRING
DOSAGE ADJUSTMENT
Hepatic vs Renal vs Both

Acrivastine

Answer 21

Renal impairment

Question 22

TABLE 189-3
Dosing Regimens for H1 Antihistamines

CONDITIONS REQUIRING
DOSAGE ADJUSTMENT
Hepatic vs Renal vs Both

Azelastine

Answer 22

Renal and hepatic impairment

Question 23

TABLE 189-3
Dosing Regimens for H1 Antihistamines

CONDITIONS REQUIRING
DOSAGE ADJUSTMENT
Hepatic vs Renal vs Both

Cetirizine

Answer 23

Renal and hepatic impairment

Question 24

TABLE 189-3
Dosing Regimens for H1 Antihistamines

CONDITIONS REQUIRING
DOSAGE ADJUSTMENT
Hepatic vs Renal vs Both

Desloratadine

Answer 24

Renal and hepatic impairment

Question 25

TABLE 189-3 Dosing Regimens for H1 Antihistamines CONDITIONS REQUIRING DOSAGE ADJUSTMENT Hepatic vs Renal vs Both Ebastine

Answer 25

Renal impairment

Question 26

TABLE 189-3 Dosing Regimens for H1 Antihistamines CONDITIONS REQUIRING DOSAGE ADJUSTMENT Hepatic vs Renal vs Both Fexofenadine

Answer 26

Renal impairment

Question 27

TABLE 189-3 Dosing Regimens for H1 Antihistamines CONDITIONS REQUIRING DOSAGE ADJUSTMENT Hepatic vs Renal vs Both Levocetirizine

Answer 27

Renal and hepatic impairment

Question 28

TABLE 189-3 Dosing Regimens for H1 Antihistamines CONDITIONS REQUIRING DOSAGE ADJUSTMENT Hepatic vs Renal vs Both Loratadine

Answer 28

Renal and hepatic impairment

Question 29

TABLE 189-3 Dosing Regimens for H1 Antihistamines CONDITIONS REQUIRING DOSAGE ADJUSTMENT Hepatic vs Renal vs Both Mizolastine

Answer 29

Hepatic impairment

Question 30

TABLE 189-7 Dosing Regimens for H2 Antihistamines CONDITIONS REQUIRING DOSAGE ADJUSTMENT Hepatic vs Renal vs Both Cimetidine

Answer 30

Renal or hepatic impairment

Question 31

TABLE 189-7 Dosing Regimens for H2 Antihistamines CONDITIONS REQUIRING DOSAGE ADJUSTMENT Hepatic vs Renal vs Both Ranitidine

Answer 31

Renal impairment

Question 32

TABLE 189-7 Dosing Regimens for H2 Antihistamines CONDITIONS REQUIRING DOSAGE ADJUSTMENT Hepatic vs Renal vs Both Famotidine

Answer 32

Renal impairment

Question 33

TABLE 189-7 Dosing Regimens for H2 Antihistamines CONDITIONS REQUIRING DOSAGE ADJUSTMENT Hepatic vs Renal vs Both Nizatidine

Answer 33

Renal impairment

Question 34

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Chlorpheniramine

Answer 34

1st gen H1

Question 35

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Cyproheptadine

Answer 35

1st gen H1

Question 36

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Diphenhydramine

Answer 36

1st gen H1

Question 37

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Hydroxyzine

Answer 37

1st gen H1

Question 38

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Tripelennamine

Answer 38

1st gen H1

Question 39

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Acrivastine

Answer 39

2nd gen H1

Question 40

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Azelastine

Answer 40

2nd gen H1

Question 41

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Cetirizine

Answer 41

2nd gen H1

Question 42

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Desloratadine

Answer 42

2nd gen H1

Question 43

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Ebastine

Answer 43

2nd gen H1

Question 44

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Fexofenadine

Answer 44

2nd gen H1

Question 45

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Levocetirizine

Answer 45

2nd gen H1

Question 46

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Loratadine

Answer 46

2nd gen H1

Question 47

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Mizolastine

Answer 47

2nd gen H1

Question 48

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Cimetidine

Answer 48

H2

Question 49

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Famotidine

Answer 49

H2

Question 50

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Ranitidine

Answer 50

H2

Question 51

TABLE 189-3 vs TABLE 189-7 Dosing Regimens for H1 Antihistamines vs Dosing Regimens for H2 Antihistamines 1st gen H1 vs 2nd gen H1 vs H2 Nizatidine

Answer 51

H2

Question 52

TABLE 189-4 Factors for Risk-to-Benefit Assessment of First-generation H1 Antihistamine Therapy Risk vs Contraindication History of cardiac arrhythmias, particularly ventricular arrhythmias

Answer 52

Risk

Question 53

TABLE 189-4 Factors for Risk-to-Benefit Assessment of First-generation H1 Antihistamine Therapy Risk vs Contraindication First trimester of pregnancy

Answer 53

Risk

Question 54

TABLE 189-4 Factors for Risk-to-Benefit Assessment of First-generation H1 Antihistamine Therapy Risk vs Contraindication Prostatic hypertrophy

Answer 54

Risk

Question 55

TABLE 189-4 Factors for Risk-to-Benefit Assessment of First-generation H1 Antihistamine Therapy Risk vs Contraindication Narrow-angle glaucoma

Answer 55

Contraindication

Question 56

TABLE 189-4 Factors for Risk-to-Benefit Assessment of First-generation H1 Antihistamine Therapy Risk vs Contraindication Concomitant use of monoamine oxidase inhibitors

Answer 56

Contraindication