antihistamine-OTC meds Flashcards Preview

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Flashcards in antihistamine-OTC meds Deck (48)
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1

Where are histamines Stored?

They are stored in the forms of granules in the mast cells (tissues) or basophils (blood)

2

How are these histamines released?

1. Immunologic release- IgE mediated, causes degranulate on exposure to antigen (Type I response)

2. Amine Drugs- can displace histamine from storage (morphine, codeine, vancomycin)

3

What receptors do histamines act on?

H1, H2, and H3

4

What is histamines effect on cardiovascular H1 receptors? how bout H2 receptors?

1. Vasodilation of arterioles-hypotension, nasal congestion

2. Increased capillary permeability (hypovolemic shock, edema, urticaria/ hives)

Effect on H2 is direct cardiac stimulation and vasodilation

5

What will be the effect of histamines on the GI-tract?

1. Contraction of smooth muscle (H1)

2. increased gastric acid secretion (H2)

6

When someone is having a bad allergic reaction there throat closes up. What effect do you think histamines have on bronchiolar smooth muscle?

Opens them SIKE.... its bronchoconstriction

7

What are the 4 major classes of antihistamines? (H1 receptor antagonists)

1. H1 receptor blockade
2. Muscarinic receptor blockade
3. sodium channel blockade
4. adrenergic receptor blockade

8

true or fals 1st gen antihistamines have additional blocking actions at non-H1 receptors?

true

9

What is one benefit of 2nd gen antihistamines compared to 1st gen when talking about H1 receptor blockade

2nd gen are highly specific for H1 receptors

10

Do both 1st gen and 2nd gen histamines have equal efficacy in blocking H1 receptors?

yes

11

Antihistamines have also work by a muscarinic receptor block. Out of the two 1st gen and 2nd gen which ones cause less sedation

2nd gen- they also have less complete CNS penetration

12

Anithistamines can act as an alpha 1 receptor block. What can this result in and what antihistamine causes this?

Can results in orthostatic hypotension

Promethazine

13

What generation of antihistamine is best for allergic rhinitis?

2nd-gen: not really sure why- maybe because its selectivity for H1 receptor is more specific

14

What can 1st gen antihistamines treat that 2nd gen can not.

1st gen antihistamines can be used for

1. cough supression- Na channel block
2. Motion sickness- H1 and M receptor block
3. Nausea and vomiting- H1 and M receptor block
4. Sleep aid for insomnia- H1 and M receptor block

15

Antihistamines are great for treating allergic rhinitis. But what it the best?

intranasal corticosteroids

16

Which gen of antihistamines has CNS penetration?

1st gen- resulting in more theraputic actions

helps with insomnia, motion sickness

17

How are antihistamines metabolized?

hepatic metabolism by CYP3A4

18

What are some the of the time frames for 1st gens to be metabolized

6-8-12 hours

19

What are some the of the time frames for 2nd gen antihistamines to be metabolized

12-24

12hrs for fexofenadine
24 hrs for loratadine

20

which gen has a greater chance of causing a sedation side effect

1st gen (benadryl)

21

Which generation antihistamine 1st or 2nd produces an antimuscarininc action causing dry mouth?

1st generation

22

Which generation antihistamine 1st or 2nd produces a paradoxical excitation

1st gen

23

Which generation antihistamine 1st or 2nd produces a postural hypotensive effect?

1 st gen has an alpha 1 blocker effect (promethazine)

24

What are the first gen antihistamines

Dimenhydrinate
diphenhydramine
Meclizine

25

Which 1st gen has the lowest sedative effect?

A. Dimenhydrinate
B. diphenhydramine
C. Meclizine

C. Meclizine

26

Which 1st gen has the highest antiemetic effect?

A. Dimenhydrinate
B. diphenhydramine
C. Meclizine

C. meclizine

27

which 1st gen antihistamine has a medium anticholinergic effect?

A. Dimenhydrinate
B. diphenhydramine
C. Meclizine

yep C meclizine again

Both A and B have the exact same effects on sedation, antiemetic, and anticholinergic

28

Can second gen antihistamine cross BBB and do they have any anticholinergic effects?

no they can not cross the BBB and they do not have any anticholinergic effects

29

what are the 2nd gen antihistamine meds?

Cetirizine
Fexofenadine
loratadine

30

Which of the following has the shortest duration?

A. Cetirizine
B. Fexofenadine
C. loratadine

B. lasts 12 hours, the others last 24