antihistamine-OTC meds

Question 1

Where are histamines Stored?

Answer 1

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

Question 2

How are these histamines released?

Answer 2

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)

Question 3

What receptors do histamines act on?

Answer 3

H1, H2, and H3

Question 4

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

Answer 4

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

Question 5

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

Answer 5

1. Contraction of smooth muscle (H1)

2. increased gastric acid secretion (H2)

Question 6

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

Answer 6

Opens them SIKE…. its bronchoconstriction

Question 7

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

Answer 7

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

Question 8

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

Answer 8

true

Question 9

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

Answer 9

2nd gen are highly specific for H1 receptors

Question 10

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

Answer 10

yes

Question 11

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

Answer 11

2nd gen- they also have less complete CNS penetration

Question 12

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

Answer 12

Can results in orthostatic hypotension

Promethazine

Question 13

What generation of antihistamine is best for allergic rhinitis?

Answer 13

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

Question 14

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

Answer 14

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

Question 15

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

Answer 15

intranasal corticosteroids

Question 16

Which gen of antihistamines has CNS penetration?

Answer 16

1st gen- resulting in more theraputic actions

helps with insomnia, motion sickness

Question 17

How are antihistamines metabolized?

Answer 17

hepatic metabolism by CYP3A4

Question 18

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

Answer 18

6-8-12 hours

Question 19

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

Answer 19

12-24

12hrs for fexofenadine
24 hrs for loratadine

Question 20

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

Answer 20

1st gen (benadryl)

Question 21

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

Answer 21

1st generation

Question 22

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

Answer 22

1st gen

Question 23

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

Answer 23

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

Question 24

What are the first gen antihistamines

Answer 24

Dimenhydrinate
diphenhydramine
Meclizine

Question 25

Which 1st gen has the lowest sedative effect? A. Dimenhydrinate B. diphenhydramine C. Meclizine

Answer 25

C. Meclizine

Question 26

Which 1st gen has the highest antiemetic effect? A. Dimenhydrinate B. diphenhydramine C. Meclizine

Answer 26

C. meclizine

Question 27

which 1st gen antihistamine has a medium anticholinergic effect? A. Dimenhydrinate B. diphenhydramine C. Meclizine

Answer 27

yep C meclizine again Both A and B have the exact same effects on sedation, antiemetic, and anticholinergic

Question 28

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

Answer 28

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

Question 29

what are the 2nd gen antihistamine meds?

Answer 29

Cetirizine Fexofenadine loratadine

Question 30

Which of the following has the shortest duration? A. Cetirizine B. Fexofenadine C. loratadine

Answer 30

B. lasts 12 hours, the others last 24

Question 31

what drug is treat nasal decongestion and only nasal decongestion?

Answer 31

sympathomimetics

Question 32

Mechanism of action for topical decongestants?

Answer 32

they stimulate alpha 1 receptors of nasal blood vessels which have been dilated due to histamines or bradykinin so they vasoconstrict theses bad boys (blood vessels that is)

Question 33

Side effect of topical decongestants?

Answer 33

rebound congestion due to local ischemia-irritation (restrict use for 3-5 days)

Question 34

What are two kinds of topical nasal decongestants?

Answer 34

Phenylephrine oxymetazoline

Question 35

from the following topical decongestants. Which is the most effective and which is the longer lasting? A. Phenylephrine B. oxymetazoline

Answer 35

A. is the most effective | B. is the longer lasting- reduces the chance of rebound congestion

Question 36

Which drug is a direct receptor agonist and which is an indirect receptor agonist? A. Phenylephrine B. Pseudoephedrine

Answer 36

A. is a direct | B. is an indirect

Question 37

How is oral phenylephrine and pseudoephedrine delivered

Answer 37

via systemic circulation to nasal vascular bed and they act on alpha 1 receptors

Question 38

which last longer oral decongestants or topical?

Answer 38

orals do. However they are less intense

Question 39

Side effects of oral decongestants?

Answer 39

they are systemic so headache, nausea, dizziness, increased BP-palpitations

Question 40

Which of the following is the safest and most effective oral decongestant? Phenylephrine or pseudoephedrine

Answer 40

pseudoephedrine | i think he said Phenylephrine doesn't even really work?

Question 41

which drug directly suppresses the cough center?

Answer 41

codeine (the good stuff)

Question 42

Uses for anittussive agents?

Answer 42

reduce frequency of cough, especially dry non-productive cough

Question 43

MOA of antitussive agents?

Answer 43

Both central and peripheral

Question 44

Most effective MOA for cough suppression?

Answer 44

drugs that are agonists at endogenous u-opioid receptors

Question 45

Which drugs are act as agonists on endogenous u-opioid receptors

Answer 45

1. Codeine 2. Hydrocodone 3. Hydromorphone 4. Dextramorphone

Question 46

Most common adverse effects of Codeine, Hydrocodone, Hydromorphone

Answer 46

Nausea, drowsiness, constipation allergic reactions

Question 47

What is the most commonly used OTC cough med?

Answer 47

dextromorphan aka robitussin

Question 48

What drugs are the first line tx for both 1. acute cough due to common cold and 2. acute cough due to upper airway cough syndrome

Answer 48

brompheniramine/pseudophedrine