Histamine & Serotonin Flashcards Preview

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Flashcards in Histamine & Serotonin Deck (42):
1

What is an H1 antagonist used for?

Allergic reactions, motion sickness, nausea and vomiting in pregnancy, sleep aids

2

What are common side effects of H1 antagonists?

Sedation, anti-muscarinic action, poisoning (especially children) with convulsions, allergy, local anesthesia

Older agents cross CNS to cause central effects

3

Where are H1 antagonists metabolized? What are the oral absorption and distribution properties?

rapid metabolism by liver microsomes

Rapidly absorbed orally and widely distributed

4

What is the mechanism of action of these drugs?

Tripelennamine (Pyribenzamine)

Meclizine (Dramamine II, Antivert)

Hydroxyzine (Atarax)

Promethazine (Phenergan)

Chlorpheniramine (Chlor-Trimeton)

Diphenhydramine (Benadryl)

H1 receptor antagonists




5

what is a common OTC sleep aid?

Tripelennamine (Pyribenzamine)

Ethylenediamine derivitive

H1 receptor antagonist

6

What histamine blockers are used for motion sickness?

Meclizine (Dramamine II, Antivert)

Hydroxyzine (Atarax)

Piperazine derivative

H1 receptor antagonist

7

What is a major side effect of diphenhydramine?

Anti-muscarinic, sedating

Ether/ethanolamine derivitive

H1 receptor antagonist


8

What is promethazine used for?

Antiemetic

Phenothiazine derivative

H1 receptor antagonist

Anti-muscarinic, sedating

9

what is chlorpheniramine?

Alkylamine derivitive

H1 receptor antagonist

Component of "cold" medications

Less sedating

10

What is the mechanism of action? What are they used to treat?

Loratadine
Fexofenadine
Azelastine
Cetirizine

2nd generation H1 receptor antagonists

2nd gen H1 blockers treat allergic rhinitis

Loratadine (Claritin)
Fexofenadine (Allegra)
Azelastine (Astelin)
Cetirizine (Zyrtec)

11

What is major difference between 1st and second gen H1 blockers?

second gen blockers poorly cross BBB, so fewer central and side effects - e.g. no sedation, although rare cadiovascular effects at high doses in loratadine (claratin) and fexofenadine (allegra)

12

What is azelastine?

2nd generation H1 receptor antagonist

Treats allergic rhinitis (intranasal spray), allergic conjunctivitis (ophthalmic solution)

13

What antihistamines can cause cardiovascular effects at high doses?

Loratadine (Claritin)
Fexofenadine (Allegra)

2nd generation H1 receptor antagonist

14

What is the mechanism of action? What are the "...tidine" drugs used for?

Cimetidine
Ranitidine
Famotidine
Nizatidine

H2 receptor antagonists; block gastric acid secretion (more so with nocturnal acid secretion than meal secretion)

15

What class of drugs are used to treat dyspepsia, duodenal and gastric ulcers, hypersecretory conditions? What is a common possible side effect?

H2 receptor antagonists; block gastric acid secretion (more so with nocturnal acid secretion than meal secretion)

CNS dysfunction

16

Of the H2 receptor antagonists, which has the most side effects? What are they?

Cimetidine (Tagamet)

Antiandrogen effects (causing impotence and gynecomastia), inhibition of P450 enzymes

17

What is Rantidine? What is the most concerning side effect?

Zantac - H2 receptor antagonist; blocks gastric acid secretion (more so with nocturnal acid secretion than meal secretion)

liver toxicity

CNS dysfunction possible

18

Of the H2 antagonists, which has the least side effects?

Nizatidine (Axid)

19

What is ketanserin? what is it used for?

Selective 5HT2A,2C receptor antagonist, as well as α1 and H1 receptor antagonist

Antihypertensive (relaxes vascular and tracheal smooth muscle), antiplatelet aggregation

20

Mechanism of action for the "...setron" drugs? Used for?

Odansetron
Granisetron

5HT3 receptor antagonists

Nausea and vomiting in chemotherapy

"...SErotoninThreeReceptor antagonist used by ONcologists"

5-HT = serotonin

21

What is Cyproheptadine?

Dual action antihistaminic and antiserotinergic

used for skin allergies (urticaria, anti-5HT1), diarrhea of carcinoid syndrome (anti-5HT2)

Side effects: Sedation, antimuscarinic

22

What class of drugs? What is a common side effect?


Methysergide
Ergonovine
Bromocriptine
Ergotamine

Ergot alkaloid

Powerful hallucinations, smooth muscle contraction (vascular and uterine)

23

Which ergot alkaloid is used to treat hyperprolactinemia? Why?

Bromocriptine (Sansert)

because it's a dopamine agonist - DA inhibits prolactin release from anterior pituitary

24

What does ergonovine treat?

Postpartum hemorrhage (Oxytocic)

25

What is methysergide? What is it used for?

ergot alkaloid

Partial agonist at all 5HT1 receptors, antagonist at 5HT2

Prophylaxis of migraines


26

What is ergotomine? What is it used for?

Ergot alkaloid

Nonspecific partial agonist at all 5HT1,2 receptors; partial agonist at α-adrenergic receptors

Prodrome of migraines

27

What are triptans? Mechanism? Used for?

Sumatriptan
Naratriptan
Rizatriptan
Zolmitriptan

Non-ergot serotonin analogs

5HT1B,D receptor agonist

Effective (70%) migraine treatment

28

Why should you analyze doses of other drugs and consider lowering them in a patient who is taking cimetidine?

Cimetidine has an effect on the cytochrome P450 system.

29

H1 receptors are found mainly:

skin, lungs, GI, nasal mucosa and blood

30

What drugs induce histamine release?

Morphine
Codeine
ACh
tubocurarine

31

H1 receptors are found:

smooth muscle, endothelium brain (hence drowsiness - CNS effect of H1 antagonism)

32

H2 receptors are found:

gastric mucosa (think H-blockers for acid reflux), cardiac muscle, mast cells, brain

33

H3 receptors are found:

CNS

34

H4 receptors are found:

eosinophils
neutrophils
CD4+ T cells

35

These classes of drugs are all what kind of drug?
Ethers or ethanolamine derivatives
Ethylenediamine derivative
Piperazine derivative
Phenothiazine derivative
Alkylamine derivative
Piperidine derivative
Azelastine

H1 receptor antagonists
Antihistamines

36

H1 receptor antagonists are largely ineffective for what conditions?

Bronchial asthma
colds

37

How is Nizatidine different from other H2 receptor antagonists?

It does not affect the cytochrome P450 system

38

Liver toxicity is a side effect of what H2 receptor blocker?

Ranitidine

39

Gynecomastia and impotence are side effects of what H2 receptor blocker?

Cimetidine

40

How are loradidine and fexofenadine different from other H1 receptor blockers?

They cross the BBB poorly, so less sedating;
fewer side effects in general

41

What is 5-hydroxytryptamine?

Serotonin

42

Release of 5-HT can be induced by what drug?

Reserpine