histamine and histamine. drugs related to autocoids.

1. HISTAMINE AND ANTI HISTAMINE
By: Dinesh mule

2. .
.
HISTAMINE
>Histamine in humans formed by DECARBOXYLATION
of the amino acid HISTIDINE.
>Large amount of histidine are found in the lungs , skin
and intestine.
>degranulation of mast cells release histamine wich is
quickly degraded by amination and methyalation.
>the enterchromaffin cells in the fundus of the stomach
release histamine whch in turn activates the H2 receptor
on the gastric parietal cells to stimulate acid secration

3. SEDATIVE
Diphenydramine, dimenhydrate,
promethazine, phenirmine ,
chlor phenramine , cyclizine ,
buclizine, meclizine
01 NON-SEDATIVE
✓ Desloloratidine, loraidine,
cetirizine, levocetrizine ,
fexofenadine acrivasatine ,
azelastine , mezolastine
02
CLASSIFICATION OF ANTI HISTAMINE
PHARMACOKINETICS
Anti histamine are well absorbed orally, widely
distributed in the body , metabolised in the liver, and are
excerted in the urine

4. HISTAMINE RECEPTOR
H2 receptor
H3 receptor
H4 receptor
H1 receptor
H2 receptor predent in the
gastric gland and mediate
gastric acid secrtion.
H3 presymaptic receptor.
Wich control the histamine
relese from the neurons of the
brain
H4 blokers seem to have
therapeutic application in
chronic inflametory deases
. H1 receptor present In the
smooth muscle and mediate
variety of action of histamine in
the body h1 blocks the many of
action of histamine

5. ACTION
SMOOTH MUSCLE
Hismaine causes contraction of the
non vascular smooth muscle. Thus
bronchum and increased in
intestinal motility are produced
NERVE ENDING
Hisa stimulate sensory nerve ending
causes pain and itching.
1) CVC
GLAND
Histamine is the powerfull stimulant
of gastric acid secrection. Qct
through h receptor. It also stimulate
the pepsin and inrensic factor.
Histamine dilates small blood
vessels resulting in hypotension and
reflex trachecardia. Cerebral blood
vessels dilate blood producing
severe thromic hedche.
CNS
Histamine function as
neuroransmiter in the cns
Sedative

6. COMPARE
01 02
RECEPTOR BLOCKED
H1 HISTAMINE
AND M1
MUSCRUNIC
H1 BLOCKERS
T1/2 4-6 HOUR 16-18 HOUR
ABILITY TO CROSS
BBB
PRESENT ABSENT
SEDATION YES NO
ANTICHOLINERGIC
AFFECTS
YES NO
LORATIDINEDIPHENYDRAMINE

7. Uses
01
02
03
04
Testing gastric
acid secrtion
To the acid secreting
ability to the stomach.
Now pentagastrin use
for thise purpose
PULMONARY
FUNCTION
To test the bronchial
hyper rectivity
Dingnosis of
phenochromocytoma
Histamine releases
catecholamines and
rises BP
Sedative

8. Non sedative anti histamine
No anticholinergic side
effects as these agents
are purly h1 blocker and
do not block cholinergic
blockers .
Some of them are long
acting .
Newer non sedative histamine have the following advantages
over sedative histamine .
They are selective h1
blockers .
No sedation because
they poorly cross the
blood brain barrier

9. ACTION
H1 RECEPTOR. ANTAGONIST BINDS TO AND BLOCK THE ACTION OF
HISTAMNE H1 RECEPTOR . THEY BLOCK THE INDUED EFFECTON
SMOOTH MUSCLE.
BLOCKADE ACTION OF HISTAMINE
First generation anti histamine causes cns depression, sedation, dizziness
inability to con.
SEDATION
Promathizine and diphenhydramine prevent motion sickness and
motionsickness and vomiting . Some of them also control vomiting of
pregnancy
Antiemetic affect or antimotion sickness
Some of them like diphenhydramine and promethazine suppress termors
and rigidity. Probly due to there anti cholinergic property
Anti PARKINSON effect
Non sedative

10. USES OF ANTIHISTAMINE
Anti histamine are usefull for the
prevention of symptoms of
allergic rections eg. Hay fiver
urticartia
ALERGIC RECTIONS
01
Given 30 to 50 minutes before
jorney antihistamine prevent
motion sickness.promethazine,
meclizine are the drug example
MOTION SICKNESS
02
Promethzine is used to prevent
drug induced and postoperative
vomiting.
ANTIEMETIC
04
Anti histamine reduces
rhinorrehea and afford
symptomatic relief in common
cold because of there anti
muscarinic property
COMMON COLD
03
NON SEDATIVE

11. THANK YOU