Antihistamines

Question 1

What is the effect of histamine on blood vessels?

Answer 1

Vasodilation (causing hypotension and nasal congestion) and increased permeability (angioedema)

Question 2

What is the effect of histamine on bronchiolar smooth muscle?

Answer 2

Bronchocontriction

Question 3

What is the effect of histamine on neurons?

Answer 3

Stimulation of sensory nerve endings causing pain and itching

Question 4

Function of histamines on the GI tract?

Answer 4

Contraction of smooth muscle(Cramping) and increase in gastric acid secretion

Question 5

What are the types of histamine receptors?

Answer 5

H1 and H2

H1 does everything except increase gastric acid secretion.

Question 6

1st generation antihistamines block what histamine receptors?

Answer 6

H1 receptors and H2 receptors

Question 7

2nd generation antihistamines block what histamine receptors?

Answer 7

Relatively selective for H1 receptors

Question 8

T/F? 1st generation and second generation antihistamines have equal efficacy in blocking H1 receptors?

Answer 8

True

Question 9

What blocking actions are preformed by antihistamines?

Answer 9

H1 receptor block
Muscarinic receptor block
Sodium channel blockade
Adrenergic (alpha 1) receptor block

Question 10

What generation of antihistamines cause lower levels of sedation?

Answer 10

2nd generation antihistamines

Question 11

Clinical uses of 1st generation antihistamines?

Answer 11

Cough suppression
Motion sickness
Nausea-vomiting of pregnancy
Sleep aid for insomnia

Question 12

Mechanism of cough suppression of antihistamines?

Answer 12

Na+ channel block

Question 13

Mechanism of motion sickness suppression of antihistamines?

Answer 13

H1 and M receptor block

Question 14

Mechanism of nausea/vomiting suppression of antihistamines?

Answer 14

H1 and M receptor block

Question 15

Mechanism of sleep aid of antihistamines?

Answer 15

H1 and M receptor block

Question 16

Why do first generation side effects cause drowsiness?

Answer 16

Increased CNS penetration

Question 17

What are the first generation antihistamines?

Answer 17

Chlorpheniramine
Diphenhydramine
Dimenhydrinate
Hydroxyzine
Meclizine
Promethazine

Question 18

What are the second generation antihistamines?

Answer 18

Cetirizine
Fexofenadine
Loratadine

Question 19

Intranasal antihistamines?

Answer 19

Azelastine