Drugs For Treating URI And Allergies

Question 1

Upper Respiratory Tract Infection

Answer 1

• Typically, a viral (90%) infection of the respiratory tract.
  ~ Cold
  ~ Flu
• Nose to Bronchi
  ~ Causes Inflammatory Response
• No anti-viral for common cold because it mutates a lot and isn’t fatal

Question 2

BK and HT

Answer 2

• Vasodilation/Increased Vessel
  Permeability
  ~ Contributes to Edema/Exudate/
  Increased Heat/Redness
• Stimulates Pain Receptors

Question 3

PG

Answer 3

• Vasodilation/Increased Vessel
  Permeability
  ~ Contributes to Edema/Exudate/
  Increased Heat/Redness
• Stimulates Pain Receptors
• PGE2 induces fever

Question 4

LT

Answer 4

• Vasodilation/Increased Vessel
  Permeability
  ~ Contributes to Edema/Exudate/
  Increased Heat/Redness
• In respiratory tract
  ~ Increased mucus production
  ~ Bronchospasm

Question 5

Upper Respiratory Tract: S&S

Answer 5

• Fever
• Nasal Congestion
  ~ Swollen respiratory tract tissues
  ~ Exudate
  ~ Mucus
• Runny Nose
• Cough
• Sore Throat
• Aches/Pains

Question 6

URI: Anti-viral

Answer 6

• No anti-viral medications treat the common cold, medications are given to address the signs/symptoms associated.
  ~ Same for flu, but there are also anti-
  virals.
• Immune system eventually defeats the virus.

Question 7

Allergy and S&S

Answer 7

• Inflammation can occur anywhere in the tract, but very commonly in the upper tract as this is where most allergens are trapped.
• Nasal congestion
• Sneezing
• Runny nose

Question 8

Sensitization to Allergen

Answer 8

• Immune system detects foreign material and builds antibodies specific to it.
  ~ Antibodies attach to mast cells.
• When exposed to allergen again the allergen attaches to the antibodies and triggers the mast cells to release HT.

Question 9

Antihistamines

Answer 9

• 4 different HT receptors throughout the body
  ~ H1
  > Respiratory Tract and Brain
  ~ H2
  ~ H3
  ~ H4

Question 10

Antihistamines Mechanism

Answer 10

• Blocks HT from binding to the H1 receptors in the respiratory tract reducing the inflammatory effects of HT
  ~ Vasodilation/Increased Permeability
  > Edema/Exudate
  ~ Pain

Question 11

Antihistamines Adverse Effects

Answer 11

• More common with first generation drugs.
  ~ Sedative: Second generation not as
  fat soluble so do not cross blood-brain
  barrier easily.
  > HT is excitatory to brain neurons
  > Blocking HT reduces neuron
  activity (causes drowsiness)
  ~ Anticholinergic Effects

Question 12

Anticholinergic Effects

Answer 12

• Blocks acetylcholine binding
• Acetylcholine Actions
  ~ Muscle contraction
  ~ Used in both the sympathetic and
  parasympathetic nervous systems
• Specific Effects
  ~ Blurred Vision
  ~ Constipation (P)
  ~ Decreased Sweating (S)
  ~ Dry Mouth (P)
  ~ Throat Irritation (P)
  ~ Pupil Dilation (P)
  ~ Urinary Hesitancy/Retention (P)

Question 13

Antihistamines: 1st Generation (drowsy)

Answer 13

• Available Since 1940’s
• Examples
  ~ Diphenhydramine/Benadryl
  ~ Chlorpheniramine/ChlorTrimeton
  > Helps respiratory symptoms but
  causes sedation
  • Better at crossing BBB

Question 14

Antihistamines: 2nd Generation (less drowsy)

Answer 14

• Available Since 1980’s
• Examples
  ~ Fexofenadine/Allegra - least sedative
  ~ Loratadine/Claritin
  ~ Desloratadine/Clarinex
  ~ Cetirizine/Zyrtec - Most sedative

Question 15

Nasal Decongestants

Answer 15

• Alpha-adrenergic receptors are a component of the sympathetic nervous system.
  ~ Activated when bound to
  norepinephrine or epinephrine.
  ~ Found in the blood vessels of the
  nasal passages.
  > Causes vasoconstriction
  • Decreases edema formation in
  tissue that line the sinuses and
  nasal passages

Question 16

Nasal Decongestants are sympathominetics…

Answer 16

• mimic epinephrine/norepinephrine to activate alpha-aderengic receptors
  ~ Alpha-adrenergic agonists
• Orally or topically (nasal spray)

Question 17

Pseudoephedrine Vs. Phenylephrine

Answer 17

• Pseudoephedrine is more effective and is metabolized slower.
• Pseudoephedrine is less convenient to buy: must ask pharmacist, show ID, sign.
  ~ Can be used to make meth
• Phenylephrine has greater common adverse effects.
  ~ Restlessness/Nervousness
  ~ Tremor
  ~ Tachycardia

Question 18

Topical Decongestants

Answer 18

• Administered via nasal spray, inhalers, or drops.
• Same effects as oral medications, but fewer adverse effects and faster acting.
  ~ Rebound congestion
  > Nose becomes used to medication
  and will swell after you stop using
• Example
  ~ Oxymetazoline/Afrin (nasal spray)

Question 19

Expectorants

Answer 19

• Drug that decreases the viscosity of respiratory tract secretions so that can be moved out of the respiratory tract
  ~ Example - Guaifenesin
  ~ Combination Product Controversy
  > Combined with Antihistamines
  • Antihistamines dry the
  respiratory tract.
  > Combined with Cough
  Suppressants

Question 20

Cough Suppressants

Answer 20

• Act on the nervous system to increase the threshold for cough.
• Indicated when cough interferes with sleep or is unproductive.
• Examples
  ~ Opiate Agonists
  ~ Dextromethorphan
  > Inhibits reflex arch - brain
  > Advantages Over Opioids
  • Doesn’t depress the respiratory
  system as much
  • Available OTC
  • Much less addictive