Seasonal Allergies: Antihistamines

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Seasonal AllergiesAntihistamines the Future

• Jacquelyn Covarrubias
• CHEM 5389
• April 24, 2007

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Outline

1. What is an Allergy?
2. Allergens
3. Allergic Rhinitis
4. Histamine and Mast Cells
5. Symptoms
6. Common Structures of Antihistamines
7. Treatments
8. Future Ideas for Dealing with Allergies

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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.

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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

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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.

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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.

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Histamine and Mast Cells
Histamine
Mast Cells
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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.

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Common Structures of Antihistamines

• Amino alkyl ethers

Bromodiphenhydramine
Diphenhydramine hydrochloride
Carbinoxamine
Benadryl (diphenhydramine hydrochloride) will be
discussed later.
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Common Structures of Antihistamines

• Substituted alkylamines

Brompheniramine
Pheniramine maleate
Chlorphenamine
These antihistamines will not be discussed later.
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Common Structures of Antihistamines

• Substituted ethylene diamines

Methapyrilene
Chloropyramine
Pyribenzamine
These first generation antihistamines are hardly
used anymore and will not be discussed further.
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Common Structures of Antihistamines

• Phenothiazine derivatives

Mequitazine
Methdilazine
Promethazine
These antihistamines will not be discussed later.
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Common Structures of Antihistamines

• Piperazine derivatives

Niaprazine
Cetirizine hydrochloride
Buclizine
Zyrtec (cetirizine hydrochloride) will be
discussed later.
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Common Structures of Antihistamines

• Tricyclic derivatives

Desloratadine
Loratadine
Ketotifen
Clarinex (desloratadine) and Claritin
(loratadine) will be discussed later.
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Common Structures of Antihistamines

• Antiallergic agents excluding corticosteroids

Azelastine hydrochloride
Fexofenadine hydrochloride
Antazoline
Astelin (azelastine hydrochloride) and Allegra
(fexofenadine hydrochloride) will be discussed
later.
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Treatments Benadryl
Diphenhydramine hydrochloride

• 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.

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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 first-generation
  histamine-receptor 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

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Treatments Clarinex
Desloratadine

• Desloratadine is a tricyclic antihistamine, which
  has a selective and peripheral H1-antagonist
  action. It has a long-lasting 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.

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Treatments Claritin
Loratadine

• Loratadine is a tricyclic antihistamine, which
  has a selective and peripheral H1-antagonist
  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.

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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.

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Treatments Astelin
Azelastine hydrochloride

• 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.

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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
  hypo-allergenic cats. They allow people with
  feline allergies to enjoy having a pet without
  having allergic symptoms.

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Allerca Cats

• 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.

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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.

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Overview
How Allergies Occur
How to treat Allergies according to symptoms