Transcript AntihistaminesJC

Seasonal Allergies:
Antihistamines &
the Future
Jacquelyn Covarrubias
CHEM 5389
April 24, 2007
Outline
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What is an Allergy?
Allergens
Allergic Rhinitis
Histamine and Mast Cells
Symptoms
Common Structures of Antihistamines
Treatments
Future Ideas for Dealing with Allergies
What is an allergy?
 Allergies are caused by an over-sensitive immune response. The
immune system normally protects the body against harmful
substances. Allergy symptoms occurs when the immune system
reacts to allergens that are generally harmless and in most
people do not cause an immune response.
 When a person with allergies breathes in an allergen such as
pollen or dust, antibodies are produced. Immunoglobulin E is a
class of immunoglobulins that includes the antibodies elicited
by an allergen. A person who has an allergy usually has
elevated blood levels of IgE. IgE antibodies attack and engage
the invading army of allergens.
 When the antibodies are stimulated by pollen and dust,
histamine and other chemicals are released. This causes
itching, swelling, and mucus production. Symptoms vary from
person to person.
Common Allergens
 Airborne particles (hay
fever)
– Grass, weeds, timothy
grass, birch trees, and
Mold spores
 Drugs
– Penicillin, sulfonamides,
salicylates, local
anesthetics, and latex
 Insect stings
– bee sting venom and
wasp sting venom
 Animal products (animal
allergy)
– Animal hair and
dander, cockroach
calyx, and dust mite
excretion
 Foods (food allergy)
– Peanuts, nuts, sesame,
pittster fruit, seafood
eggs, peas, beans,
soybeans, celery, soy,
milk, wheat, and corn
Allergic Rhinitis
 Allergic rhinitis is the fifth most
prevalent chronic disease in the United
States, affecting up to 40 million adults
and children each year.
 Allergic rhinitis costs the nation
approximately $5.3 billion in direct and
indirect costs (including time lost from
work and school) and accounts for
about 10,000 absences from school.
Histamine and Mast Cells
 When you are exposed to an
allergen, a specific type of
white blood cell called the
mast cell, which is located in
the membrane lining the
nose and sinuses, releases a
chemical called histamine.
Histamine attaches to its site
of action called receptors on
nearby blood vessels,
causing them to dilate or
enlarge, leading to redness,
swelling, itching, and
changes in the secretions.
Histamine and Mast Cells
Histamine:
Mast Cells:
Symptoms
 Nose: swelling of the nasal
mucosa (allergic
rhinitis)
 Eyes: redness and itching
(allergic conjunctivitis)
 Airways:
bronchoconstriction,
wheezing, itchy or
sore throat, post nasal
drip, and cough
 Ears: feeling of fullness,
possibly pain, and
impaired hearing due
to the lack of
eustachian tube
drainage.
Common Structures of Antihistamines
Amino alkyl ethers
Bromodiphenhydramine: Diphenhydramine hydrochloride:
Carbinoxamine:
Benadryl (diphenhydramine hydrochloride) will be
discussed later.
Common Structures of Antihistamines
Substituted alkylamines
Brompheniramine:
Pheniramine maleate:
Chlorphenamine:
These antihistamines will not be discussed later.
Common Structures of Antihistamines
Substituted ethylene diamines
Methapyrilene:
Chloropyramine:
Pyribenzamine:
These first generation antihistamines are hardly
used anymore and will not be discussed further.
Common Structures of Antihistamines
Phenothiazine derivatives
Mequitazine:
Methdilazine:
Promethazine:
These antihistamines will not be discussed later.
Common Structures of Antihistamines
Piperazine derivatives
Cetirizine hydrochloride:
Niaprazine:
Buclizine:
Zyrtec (cetirizine hydrochloride) will be
discussed later.
Common Structures of Antihistamines
Tricyclic derivatives
Desloratadine:
Loratadine:
Ketotifen:
Clarinex (desloratadine) and Claritin (loratadine) will be discussed
later.
Common Structures of Antihistamines
Antiallergic agents excluding corticosteroids
Azelastine hydrochloride:
Fexofenadine hydrochloride:
Antazoline:
Astelin (azelastine hydrochloride) and
Allegra (fexofenadine hydrochloride) will be
discussed later.
Treatments: Benadryl
Diphenhydramine hydrochloride:
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Diphenhydramine is a first
generation antihistamine drug.
It works by blocking the effect of
histamine at H1 receptor sites.
This results in effects such as the
reduction of smooth muscle
contraction, making
diphenhydramine a popular choice
for treatment of the symptoms of
allergic rhinitis, hives, motion
sickness, and insect bites and
stings.
Side effects include: drowsiness,
possibilities of motor impairment,
dry mouth and throat, flushed
skin, rapid or irregular heartbeat,
blurred vision at near point,
abnormal sensitivity to bright
light, pupil dilatation, urinary
retention, constipation, difficulty
concentrating, short-term memory
loss, visual disturbances,
hallucinations, confusion, erectile
dysfunction, and delirium.
Treatments: Allegra
Fexofenadine hydrochloride:
• Fexofenadine hydrochloride
is a second-generation
antihistamine, which does
not cross the blood-brain
barrier, and so causes less
drowsiness than firstgeneration histaminereceptor antagonists.
 Fexofenadine hydrochloride
is a histamine H1-receptor
antagonist.
 Treats sneezing, rhinorrhea,
itchy nose/palate/throat,
and itchy/watery/red eyes.
 Common side effects:
nausea, vomiting, weakness,
drowsiness, sleepiness, and
depression
Treatments: Clarinex
Desloratadine:
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Desloratadine is a tricyclic
antihistamine, which has a
selective and peripheral H1antagonist action. It has a longlasting effect and does not cause
drowsiness because it does not
readily enter the central nervous
system.
Clarinex treats sneezing, runny
nose, itching and watering of
the eyes, and other allergic
symptoms.
Common Side Effects: sore
throat, dry mouth, drowsiness,
fatigue, headache, and
gastrointestinal disturbances.
Treatments: Claritin
Loratadine:
 Loratadine is a tricyclic
antihistamine, which has a
selective and peripheral H1antagonist action. It has a
long-lasting effect and does
not normally cause
drowsiness because it does
not readily enter the central
nervous system.
 Loratadine treats watery
eyes, runny nose, itching
eyes, and sneezing. It may
also be used to treat hives.
 Common Side Effects: dry
mouth, headache and
gastrointestinal
disturbances.
Treatments: Zyrtec
Cetirizine hydrochloride:
 Cetirizine hydrochloride
is a racemic selective H1
receptor antagonist.
 Cetirizine hydrochloride
treats itchy, red, and
watery eyes, sneezing,
runny, and itchy nose,
postnasal drip and
itching from hives.
 Common side effects:
sleepiness, fatigue, or
dizziness, headache,
and dry mouth.
Treatments: Astelin
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Azelastine hydrochloride is the only
prescription antihistamine approved
to treat nasal congestion.
It is a steroid free and
pseudoephedrine free antihistamine
nasal spray which provides relief
from congestion, itchy or runny
nose, sneezing, and postnasal drip.
Astelin, the Azelastine hydrochloride
brand name, blocks the effects of
histamine.
The medicine is a nasal spray which
enables quicker relief from allergy
symptoms.
Astelin is unique because it treats
symptoms caused by both allergens
and irritants.
Because Astelin does not contain a
topical vasoconstrictor like other
nasal decongestants, it does not
cause chronic nasal stuffiness.
Common side effects: bitter taste,
headache, nasal inflammation or
burning, and drowsiness.
Azelastine hydrochloride:
Future Ideas
 According to the
American Academy of
Allergy, Asthma and
Immunology, 30 million
Americans suffer from
some form of cat allergy.
 Allerca has produced
the world's first hypoallergenic cats. They
allow people with feline
allergies to enjoy having
a pet without having
allergic symptoms.
Allerca Cats
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The hypo-allergenic cats are
made by focusing in on the cat
allergen that causes the
symptoms.
Normally, the cat allergen can
remain airborne for several
months and is ten times
smaller than pollen or dust
particles.
There is a glycoprotein
secreted by the cat's skin and
salivary glands whose
production depends on the Fel
d 1 gene.
The company altered the
protein to allow the cat to
secrete a genetic divergent Fel
d 1 that does not trigger
symptoms of allergies and is
not harmful to the cat. The
cats were tested on people with
cat allergies and proved that
these new cats did not cause
any symptoms.
Only $9895!!
 ALLERCA began deliveries of
GD kittens to eager
customers at the end of
2006.
 You too can now own an
ALLERCA GD kitten. The
price is $6950 per kitten.
Orders made on or before
May 1, 2007 qualify for the
initial price of $3950.
 A processing and
transportation fee of $995 is
due eight weeks prior to
delivery.
 The Premium Placement fee
is $1,950 to guarantee your
delivery in 1 year rather than
2 years.
Overview
How Allergies Occur:
How to treat Allergies according to symptoms: