Lecture 25/26

Question 1

histamine synthesis

Answer 1

histidine loses CO2 via L-histidine decarboxylase
in mast cells and basophils

Question 2

histamine metabolism

Answer 2

oxidation via diamine oxidase reaction
methylation via histamine-N-methyltransferase reaction
into inactive forms imidazole acetic acid riboside and N-methylimidazole acetic acid

Question 3

histamine storage

Answer 3

in granules as complexes –> sulfated polysaccharides, heparin sulfate, chondroitin sulfate, and proteases
non-mast cells –> in nerve terminals (as NT) and fundus of stomach (for acid secretion stimulation)

Question 4

Antigen mediated release mechanism

Answer 4

binding of IgE antibodies to FceR
binding of antigen to IgE antibodies
clustering of FceR receptors
influx of Ca2+ via CRAC

Question 5

H1 receptors

Answer 5

cause contraction of smooth muscles (increased Ca2+) and vasodilation (decreased Ca2+)
via phosphoinositol pathway
distributed throughout cardiovascular system, respiratory system, and GI smooth muscle

Question 6

H2 receptors

Answer 6

distributed in cardiovascular system, GI smooth muscle, and the stomach
increases cAMP

Question 7

H1 in vascular endothelium

Answer 7

increase in nitric oxide and increase contraction of endothelial cells

Question 8

H2 in vascular muscle

Answer 8

relaxation (vasodilation)

Question 9

histamine in the heart

Answer 9

moderate increase in rate and force of contraction
H2 increase in SA node contraction
reflex tachycardia

Question 10

histamine involvement in vasodilation

Answer 10

H1 in endothelium
H2 in smooth muscle

Question 11

histamine in respiratory system

Answer 11

H1 mediated constriction of bronchial smooth muscle

Question 12

1st generation antihistamines

Answer 12

brompheniramine
cyproheptadine
diphenydramine
promethazine
hydroxyzine
pyrilamine

Question 13

brompheniramine

Answer 13

dimetapp
class - alkylamine

Question 14

cyproheptadine

Answer 14

periactin
class - piperidine
property - anti-serotonin
USE - headaches

Question 15

diphenhydramine

Answer 15

benadryl
class - ethanolamines
property - sedation
USE - sleep aid

Question 16

promethazine

Answer 16

phenergan
class - phenothiazine
property - extrapyramidal, a adrenergic antagonism, sedation
USES - sleep aid, local anesthetic
SIDE EFFECTS - dystonia, akathisia, hypotension

Question 17

hydroxyzine

Answer 17

atarax
class - piperazines

Question 18

pyrilamine

Answer 18

class - ethylenediamine
USE - local anesthetic

Question 19

anti-cholinergic effects of 1st gen antihistamines

Answer 19

anti-motion sickness
anti-emetic (nausa/vomiting)
CNS access prominent

Question 20

contraindications of 1st gen antihistamines

Answer 20

urinary retention and narrow angle glaucoma
caused by decreased urination and dry mouth

Question 21

sedation mechanism

Answer 21

blockade of H1/H2 receptors in wakefullness-promoting circuits
interacts with alcohol, anxiolytics, and antipsychotics

Question 22

2nd gen antihistamines

Answer 22

loratidine (claritin)
desloratadine (clarinex)
fexofenadine (allegra)
cetrizine (zyrtec)
levocetrizine (xyzal)
terfenidine (seldane)

Question 23

cetrizine specific

Answer 23

may also block LTC4, neutrophil migration, and eosinophil infiltration

Question 24

2nd gen antihistamine side effect profile

Answer 24

decreased lipid solubility so little to no CNS affects
thus no sedation, anti-muscarinic acts, anti-emetic acts, and no anti-motionsickness acts

Question 25

rhinorrhea allergic

Answer 25

histamine indirectly stimulates mucus discharge via H1 receptors on nerve endings

Question 26

rhinorrhea common cold

Answer 26

virus stimulates reflex independent of peripheral H2 receptors

Question 27

1st gen common cold treatment

Answer 27

inhibits rhinorrhea and sneezing effects
(second gen is not as effective)

Question 28

common drugs to treat rhinorrhea

Answer 28

olopatadine (patanol) - eye drop or nasal spray
azelastine (astelin) - eye drop or nasal spray
ketotifen (zaditor) - eye drop

Question 29

side effect of drugs to treat rhinorrhea

Answer 29

drowsiness if oral or nasal spray dosage form

Question 30

clinical uses of antihistamines

Answer 30

rhinorrhea
chronic urticaria
motion sickness
adjunct with epinephrine to treat anaphylaxis

Question 31

motion sickness drugs

Answer 31

dimehydrinate (dramamine) - combination product of diphenhydramine and chlorotheophylline salt
meclizine (antivert)
promethazine (phenergan)

Question 32

adjunct drugs to treat anaphylaxis

Answer 32

epinephrine is the psychological antagonist with diphenhydramine delivered parenterally

Question 33

early phase response with T cells

Answer 33

nerves lead to sneeze
glands lead to runny nose
vessels lead to congestion

Question 34

late phase response with T cells

Answer 34

release of chemoattractant factors –> inflammation –> congestion

Question 35

fluticasone

Answer 35

flonase
very low systemic absorption from intranasal dose
slow onset so may take a couple of days to develop max benefit
may suppress HPA axis with prolonged high dose

Question 36

budesonide

Answer 36

rhinocort
1/3 of the dose is absorbed within an hour
may suppress HPA axis with prolonged high dose
slow onset may take a couple of days to develop max benefit

Question 37

action of glucocorticosteroids in allergic rhinitis

Answer 37

decrease cytokine production in TH2 cells
decrease mucin secretion in glands and goblet cells