Autocoids

Question 1

histamine

Answer 1

beta imidazolylethylamine

Question 2

histamine metabolism

Answer 2

oxidation

methylation

Question 3

histamine release inhibition

Answer 3

beta adrenergic agonist/ methylxanthines - increase cAMP - INHIBITION OF RELEASE

Question 4

histamine release from exocytosed granules require

Answer 4

sodium

Question 5

H4 agonist

Answer 5

4-methylhistamine

Question 6

H4 receptors

Answer 6

on basophil, mast cell, eosinophils - chemotaxis- inflammation

Question 7

Histamine

Answer 7

vasodilation - smaller vessels
vasoconstriction - larger arteries and veins
flushing
capillary permeability increased
increased co and heart rate

fall in bp

• persistent slow via h2
• fast short via h1

pulsatile headache

Question 8

Histamine - vasodilation

Answer 8

H1 - EDRF mediated

H2 - directly

Question 9

intradermal histamine

Answer 9

triple response
capillary dilation - red spot
increased permeability - wheal
arterioles dilate - flare

Question 10

isolated heart

Answer 10

H2 mediated stimulation

H1 - negative dromotropic effect

Question 11

histamine on bronchus

Answer 11

contraction

Question 12

histamine on intestine

Answer 12

contraction

Question 13

visceral smooth muscles

Answer 13

H1 - contraction

H2 - may cause relaxation

Question 14

histamine on glands

Answer 14

increase acid, pepsin

h2 on parietal cells

Question 15

h2 increase cAMP

Answer 15

activate H K ATPase pump

Question 16

histamine on sensory nerves, autonomic ganglion, adrenal medulla

Answer 16

stimulated

Question 17

intracerebral histamine

Answer 17

rise in BP, cardiac stimulation, behavioural arousal, hypothermia, vomiting and ADH release

Question 18

LTD4 and PAF

Answer 18

asthma

anaphylactic fall in bp

Question 19

Histamine - role

Answer 19

gastric secretion - H2
hypersensitivity - H1
appetite - brain H1
wakefulness

h2 mediated regulation of:
body temperature, cvs, thirst
inflammation
tissue growth and repair
vascular headache

Question 20

beta histine

Answer 20

selective H1 agonist

meniere disease - vasodilation in ear

Question 21

histamine liberators

Answer 21

ab:ag reaction
tissue trauma
polymers - dextran, pvp (polyvinyl pyrrolidine)
surface acting agents - tween 80
some bqsic drugs - even some antihistamines

counter acted by H1, (and H2) drugs

Question 22

antihistamines - actions

Answer 22

blocks - bronchoconstriction, vasodilation of capillaries, vasoconstriction of larger vessels, intestine contraction, ttiple response, hypersensitivity i, motion sickness

sedative (older)

antitussive

anti muscarinic

local anesthesia (membrane stabilization)

fall in bp (iv injection)

Question 23

antihistamines

Answer 23

route - oral, parenteral
metabolism - liver
excretion - urine
duration of action - 4-6 hours
penetrate brain (older ones)

Question 24

antihistamines

Answer 24

Promethazine 
Chlorpheniramine 
Fexofenadine 
Diphenhydramine 
Hydroxyzine 
Dimenhydrinate 
Triprolidine 
Pheniramine 
Cyproheptadine 
Astemizole 
Loratadine 
Cetirizine 
Mizolastine

Question 25

antihistamines side effects

Answer 25

Sedation, motor incoordination, fatigue
epigastric distress
anticholinergic side effects
headache

Question 26

acute overdose of antihistamines

Answer 26

central excitation, tremors, hallucinations, muscular incoordination, flushing, convulsions, hypotension, fever, respiratory and cvs failure

Question 27

2nd gen H1 antagonist

Answer 27

no sedation, no anticholinergic side effects

also inhibits paf and LTD4

poor antipruritic, antiemetics and antitussive effects

Question 28

astemizole, terfenadine

Answer 28

inhibit delayed rectifier K channels - prolong qtc - torsades de pointes

Question 29

fexofenadine

Answer 29

allergic rhinitis - 120mg OD
urticaria - 180 mg OD

rapid absorption
excreted - unchanged - urine, bile
half life - 11-16 hours

Question 30

loratidine

Answer 30

metabolised by 3A4
t1/2- 17 hr

adr - seizures

urticaria, atopic dermatitis

active metabolite - desloratidine - half dose required; cardiac safety, non interference with psychomotor performance

Question 31

citrizine

Answer 31

SGA H1
metabolite of hydroxyzine
mild sedation
not metabolised

antiallergy - inhibits release of cytotoxic mediators fro platelets and eosinophils

utricaria, allergic rhinitis, asthma

Levo cetrizine - half dose required

Question 32

azelastine

Answer 32

topical
inhibits histamine release triggered by paf LTD4
downregulate icam-1
t1/2- 24 hour
active metabolite - 3A4
side effect- stinging, altered taste

Question 33

mizolastine

Answer 33

non sedating
allergic rhinitis, utricaria
t1/2 - 10 hrs
SINGLE DOSE

Question 34

ebastine

Answer 34

converted to carbastine cyp3A4
t1/2 - 10-16 hrs

nasal, skin allergies

some reports of arrhythmias

Question 35

rupatidine

Answer 35

antihistaminic
paf antagonist

allergic rhinitis

Question 36

antihistamines - uses

Answer 36

allergic disorders, pruritides (older), common cold, motion sickness, vertigo (cinnarizine, dimenhydrinate), preanesthetic, cough, parkinson, acute muscle dystonia, as sedative, hypnotic, anxiolytic

Question 37

vertigo

Answer 37

Labyrinthine suppressant- inhibit cholinergic pathway

antihistamines - cinnarizine, dimenhydrinate, diphenhydramine, promethazine
anticholinergic- atropine, hyoscine
antiemetics phenothiazine- prochlorperazine, thiethylperazine

vasodilators- improve blood flow to labyrinthine- nicotinic acid, cidergocrine, betahistine
diuretics - decrease fluid pressure- acetazolamide, thiazide, amiloride

modify the sensation
anxiolytics - diazepam
antidepressants- amitriptyline

corticosteroids

Question 38

common cold

Answer 38

antihistamines- anticholinergic, sedative action