Exam1Lec7Histamines

Question 1

Allergy is also referred to as atopy which is what?

Answer 1

a disorder of the immune system resulting in excessive histamine release.

Question 2

What are common allergic rxns? Allergic rxns can occur to what?

Answer 2

eczema, hives, hay fever, asthma
food allergens, drug allergens, and to the venom of stinging insects such as wasps and bees

Question 3

What are the first-gen antihistamine?

Answer 3

Chlorpheniramine
Diphenhydramine
Hydroxyzine

Question 4

What are the second-gen antihistamine?

Answer 4

Cetirizine
Azelastine (intranasal)
Loratadine
Fexofenadine

Question 5

What is the main difference between 1st and second generation antihistamines?

Answer 5

1st can cross the blood brain barrrier and cause sedation

2nd does not cross the BBB (not sedative)

Question 6

What are autocoids and what do they include?

Answer 6

Endog cmpd that are produced by neural and non-neural tissues. Autacoids include monoamines such as histamines and serotonin, prostaglandins as well as leukotrienes.

Question 7

Histamine can be released is response to what?

Answer 7

Injury or a local hormone (also prostaglandins & leukotrienes) in response to an allergic rxn.

Question 8

High concentration of histamine may lead to

Answer 8

anaphylactic shock

Question 9

What do drugs for autocoids do to alleviate allergic rxns?

Answer 9

inhibit the synthesis or block the receptor for autocoids

Question 10

The drugs that activate autocoid receptors are helpful for what?

Answer 10

Inducing labor, fighting migraines headaches and other purposes

Question 11

How are histamines made?

Answer 11

Made by Histidine (amino acid) by the enzyme L-Histidine decarboxylase

histamines are stores in granules (vesicles)

Question 12

Anyibody-antigen complex interacts with GPCR’s where?

Answer 12

Mast cells and basophils (abundant in the GI tract, skin, and RT) resulting in release of histamines

Question 13

HISTAMINES are metabolized by ____ enzymes within the GI tract and liver

Answer 13

n-methyltransferase

Question 14

Degranulation of Mast cells

stimuli that incr ____ increases ____.

Answer 14

cGMP, histamine

those incr the cAMP, lower histamine

Question 15

Histamine is an ____ for GPCR.

Answer 15

agonist

Question 16

Activation of Histamine receptors result in what?

Answer 16

incr in cGMP on smc and neurons

Question 17

Activation of what isoform of Histamine receptor are involved in allergic rxns?

Answer 17

H1(gpcr)

causing dermatiis, rhinits, conjuctivitis

Question 18

Activation of H1 results in what 4 things?

Answer 18

1. Vasodilation (resulting in a decr in blood pressure)
2. Incr vascular permeability (leads to erythema, congestion, edema, inflammation)
3. Nerve ending cause pruritus (itching) and in lugs initiates the cough reflex.
4. Bronchoconstriction and contraction of most gastrointestinal smooth muscles

Question 19

Antihistamines are
antagonist?
inv agonsists?
agonists?
of H1 receptor

Answer 19

inverse agonists

Antihistamines are inverse agonists of mainly H1 type histamine receptors (G protein-coupled receptors).

Question 20

Antihistamines block production of what?

Answer 20

cGMP

Question 21

Second generation anti-histamines have a higher or lower lipid: water coefficient

Answer 21

lower

When administered orally, antihistamine drugs are absorbed rapidl

Question 22

For elimination, the anti-histamine drugs are metabolized in the ____ by ____.

Answer 22

liver, n-methyltransferase

Some antihistamines can be excreted into urine unchanged.

Question 23

In addition to treating allergies, 1st gen antihistamines also treats and prevents what?

Answer 23

treat nausea, vomiting
prevents motion sickness and vertigo

also induces sedation

Question 24

The second-gen antihis are mainly used for what?

Answer 24

Treat allergies.

Question 25

What are the adverse effects of Diphenhydramine and to a lesser extent other First-generation antihis? These effects are similar to what?

Answer 25

sedation

Block muscarinic receptors causing dry mouth, blurred vision, tachycardia, and urinary retention

These effects are similar to atropine side-effects ( know this)

These effects are similar to atropine side-effects ( know this)

Question 26

What are the adverse effects of Azelastine?

Answer 26

cause dizziness, headache, nasal irritation, dry-mouth, and weight gain.

2nd gen