Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Owenpharm Block 2 > Histamine > Flashcards

Histamine Flashcards

To rock the heck out of histamine!

1
Q

From what essential amino acid does histamine come from?

A

L-histidine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What alteration can account for histamine intolerance in approximately 1% of the population?

A

Alteration in histamine degrading enzymes (DAO or HNMT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What three roles does Histamine have?

A
  1. Mediator of immediate allergic inflammatory reactions
  2. Role in gastric acid secretion
  3. Neurotransmitter and neuromodulator
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where are the highest amounts of Histamine located? (3 locations)

A
  1. Lungs
  2. Skin
  3. GI tract
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where are “pools” of histamine stored in tissues & blood?

A

Tissues - Mast cells

Blood - Basophils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How are the “pools” of histamine managed in basophils?

A

Synthesized and stored in secretory granules in an inactive form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Histamine is bound to a proteoglycan intracellularly. What is this glycan in mast cells? in basophils?

A

Heparin-sulfate and ATP in mast cells

Chondroitin-sulfate in basophils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Is the turnover of Histamine in mast cells and basophils fast or slow?

A

Slow turnover

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is histamine handled differently in non-mast cells (gastric mucosa, epidermis, neurons)? (4 points)

A
  1. There are no granules
  2. Histamine is continuously synthesized and released
  3. There is a rapid turnover
  4. Histidine decarboxylase levels correlate with activity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the immediate effects of histamine release? (5 items)

A
  1. Burning/itching sensation
  2. Intense warmth
  3. Skin reddens
  4. BP decreases
  5. HR increases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the effects of histamine release within minutes (different than immediate)? (2 items)

A
  1. BP recovers

2. Hives appear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the process of histamine release when there has been prior exposure to the antigen. (3 steps)

A

Binding of IgE to FceRI on mast cells
Antigen binding to IgE
Activation of mast cell with release of mediators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the process of first exposure to an allergen in relation to histamine release.

A

Antigen activation of TH2 cells
Stimulation of IgE class switching in B cells
IgE secreted antibodies engage in future encounters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How is drug/peptide/venom release of histamine different that allergic release? (2 points)

A

It is not antigen-antibody mediated

Results in direct stimulation without prior exposure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What drugs cause direct stimulation of histamine release? (5 items)

A 
Succinylcholine
Morphine
Curare
Plasma expanders (dextran, PVP)
Vancomycin ("red-man syndrome")
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What peptides can cause direct stimulation of histamine release? (3 items)

A

Bradykinin
Complement
Substance P (release during tissue injury)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What venom can cause direct stimulation of histamine release?

A

Wasp venom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the mechanism for direct stimulation of histamine release?

A

Increase in intracellular calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the clinical picture of Red-man syndrome? (2 items)

A

Rash to face, neck, upper torso

Hypotension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the name for the inhaled anti-inflammatory, anti-histamine agent used in asthma?

A

Cromolyn Sodium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the mechanism for Cromolyn Sodium? (2 points)

A

Stabilizes mast cell membrane to prevent release of histamine
Prevents mast cell degranulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the primary route of admin for Cromolyn sodium?

What are the alternatives?

A

Inhalation

Oral, Nasal, Ophthalmic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the therapeutic utility of Cromolyn sodium? (3 points)

A

Chronic asthma control
Prophylaxis of bronchospasm (allergen- or exercise-induced)
Not a rescue medication!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the major uses for the Nasal, Ophthalmic, and Oral preparations of Cromolyn sodium?

A

Nasal - Allergic rhinitis
Ophthalmic - Conjunctivitis
Oral - Systemic mastocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the mechanism of action for Omalizumab? (2 points)

A

Decreases amount of antigen specific IgE

Binds tightly to free IgE to prevent FceRI binding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the route of administration for Omalizumab?

A

SQ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What adverse effects should one look for with Omalizumab? (2 points)

A

Injection site reaction

Anaphylaxis after first dose

28
Q

What are the H1 histamine receptors primarily located?

What does activation of these affect?

A

Endothelial cells

Vasodilation

29
Q

How does H1 & H2 receptor combined activation contribute to vascular dilation? (3 points)

A

H1 system coupled to increase in calcium
H1 receptors activate NO synthase
H2 receptors couples to increase in cAMP

30
Q

What effect does H1 receptor activation have on large vessels?

A

vasoconstriction

31
Q

What effect does activation of H1 and H2 have on BP overall?

A

decrease

32
Q

Activation of H1 receptors have what effect on vascular permeability?
Why?

A

Increased
Located on post-capillary venules-endothelial cells
Contraction of these cells causes exposure of basement membrane

33
Q

What effect do H2 receptors have on cardiac myocytes? (2 points)

A

Increased contractility

Increased electrical conduction

34
Q

What effects do H1 and H2 receptors have on bronchioles? (2 points)

A

H1 - contraction

H2 - relaxtion (minor)

35
Q

Which histamine receptor causes intestinal smooth muscle contraction?

A

H1

36
Q

Which histamine receptor causes gastric acid secretion?

A

H2

37
Q

Which histamine receptor causes pain & itching in peripheral nerve endings?

A

H1

38
Q

Which H receptor is responsible for increased arousal/wakefulness?

A

H1

39
Q

What are the 4 first generation H1 receptor blockers for this course?

A

Diphenhydramine
Dimenhydrinate
Chlorpheniramine
Promethazine

40
Q

Which first generation H1 blocker also blocks dopamine receptors?

A

Promethazine

41
Q

What are the 4 second generation H1 blockers for this course?

A

Fexofenadine
Loratadine
Cetirizine
Desloratidine

42
Q

What is the difference between first and second generation H1 receptor blockers?(2 points)

A

Second generation have little to no CNS effects

First generation also have mild/moderate muscarinic antagonism in CNS

43
Q

What type of activity are H1 receptor blockers classified as having?

A

Inverse agonism

44
Q

What are the major therapeutic effects of H1 antagonists?

A

Inhibition of vascular permeability
Suppressed itching
No effect on blood pressure
No effect on bronchoconstriction

45
Q

What effect do 1st generation H1 blockers have on CNS? (2 points)
Is it different in children?

A

Sedation and Anti-cholinergic reduction in motion sickness

Yes, can cause stimulation in children

46
Q

Can anti-cholinergic effects be seen with H1 blockers?
What kinds?
Which generation?

A

Yes
Dry mucus membranes, Urinary retention, “anti-cholinergic syndrome”
1st generation only.

47
Q

What are the oral pharmacokinetics of H1 blockers? (2 points)

A

Rapid absorption

Peak conc. 1-2 hours

48
Q

How are 2nd generation H1 blockers metabolized?

A

Liver P450 (CYP3A4/CYP2D6)

49
Q

What is the metabolite of Terfenadine?

A

Fexofenadine

50
Q

What is the metabolite of Loratadine?

A

Desloratadine

51
Q

Hydroxyzine is metabolized to what active agent?

A

Cetirizine

52
Q

How does a 1st generation H1 blocker cause sedation?

A

Central H1 effect and central anti-cholinergic effect

53
Q

Which 2nd generation H1 blocker has the most sedative effect?

A

Cetirizine

54
Q

Have there been any adverse effects seen of loratadine on QT interval?

A

No

55
Q

Which H1 blockers exhibit a noticeable anti-cholinergic effect useful for motion sickness?

A

dimenhydrinate (dramamine)
promethazine (phenergan)
diphenhydramine (benadryl)

56
Q

Off-label uses and the used (4 points)

A

Sleeping aid - Diphenhydramine
Vestibular disturbance - Dimenhydrinate
Nausea/Vomiting - Promethazine
Early stage Parkinson’s - Diphenhydramine

57
Q

What are the indications for H2 receptor antagonists? (4 points)

A

Relief of symptoms peptic ulcer disease
Gastroesophageal reflux disease
Peptic ulcer secondary to H. pylori
Gastric injury from NSAIDS

58
Q

What is the mechanism of action for H2 receptor antagonists?

A

H2 receptor stimulation on parietal cells increases adenylyl cyclase, cAMP, and PKA –> this increases acid production.

H2 blockers stop this activity.

59
Q

Is H2 stimulation the terminal step in acid production?

A

No, Gastrin and ACH also have direct effect on parietal cells. Proton pump is terminal step.

60
Q

What type of inhibitor are H2 antagonists?

A

Reversible competitive inhibitor (can act as inverse agonist)

61
Q

What is the importance of the inverse agonism of H2 antagonists?

A

Inhibition of fasting acid secretion and inhibition of nocturnal gastric acid secretion is a big determinant in the healing of ulcers.

62
Q

What common side effects are seen with H2 blockers?

A

Diarrhea, headache, drowsiness

63
Q

What are less common effects seen mostly with IV administration in elderly patients?

A

confusion
delirium
slurred speech

64
Q

What is the significance of Cimetidine that is not present with other H2 blockers?

A

Inhibition of P450 metabolism

65
Q

What are the three H2 blockers for this course?

A

Cimetidine
Famotidine
Ranitidine

66
Q

Long term use of high doses of Cimetidine can lead to what undesirable effects in men?

A

Decreased testosterone binding

Gynecomastia due to inhibition of estradiol hydroxylation

67
Q

What is the order of potency of H2 blockers?

A

Famotidine (Pepcid) > Ranitidine (Zantac) > Cimetidine (Tagamet)

Owenpharm Block 2 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions