Antihistamines and Allergic Rhinitis/URI Drugs

Question 1

Histaminergic neurons

Answer 1

Located exclusively in the posterior hypothalamus, associated with peak release at night as regulated by circadian rhythm

Question 2

Agents that trigger histamine release without prior sensitization (3)

Answer 2

Drugs, radiocontrast media, direct cell injury

Question 3

Efffects of H1 receptor stimulation

Answer 3

• Vasodilation
• increased capillary permeability
• bronchoconstriction
• increased itching or pain

Question 4

Can you treat asthma with antihistamine?

Answer 4

No, the antihistamine has minimal benefit

Question 5

effects of H2 stimulation (1)

Answer 5

Secretion of gastric acid

Question 6

Can antihistamines treat anaphylaxis?

Answer 6

No, they have minimal impact and are used as primarily adjunctive therapy

Question 7

2 classes of H1 antagonist

Answer 7

1st gen - diphenhydramine and chlorpheniramine

2nd gen - cetirizine, levocetirizine, fexofenadine, loratidine, desloratidine

Question 8

Diff between 1st and 2nd gen H1 antagonists

Answer 8

• 1st gen are highly sedating, 2nd not very much
• 1st gen have anticholinergic effects leading to dry mouth, difficulty in micturition, tachycardia, constipation, virtually absent in 2nd generation

Question 9

H1 antagonist mech of action

Answer 9

Competes with antihistamine for H1 receptors, does not inhibit histamine already attached to receptors so therefore should be taken 2 to 5 hours before allergen exposure (prophylactically)

Question 10

Therapeutic uses of H1 antagonist (5)

Answer 10

• mild allergy
• severe allergy (supplemental)
• motion sickness
• insomnia
• useless for the common cold

Question 11

ADR’s of H1 (primarily 1st gen but some 2nd gen) antagonist (4)

Answer 11

• sedation (1st gen)
• psychomoor performance
• GI disturbances
• anticholinergic effects (primarily 1st gen)

Question 12

Drug interactions of H1 antagonists (2)

Answer 12

• CNS depressants

- alcohol

Question 13

Name the 5 big 2nd gen H1 blockers (brand name and generic)

Answer 13

Fexofenadine (allegra)
Cetirizine (zyrtec)
Loratadine (claritin and alavert)
Desloratadine (clarinex)
Levocetirizine (xyzal)

Question 14

Loratadine (claritin and Alavert) indications (2)

Answer 14

• allergic rhinitis

- chronic idiopathic urticaria

Question 15

Cetirizine (zyrtec) indications (3)

Answer 15

• seasonal allergic rhinitis
• Perennial allergic rhinitis
• Chronic idiopathic urticaria

Question 16

Fexofenadine (allegra) indications (2)

Answer 16

• seasonal allergic rhinitis

- Chronic idiopathic urticaria

Question 17

What decreases the absorption of allegra?

Answer 17

Some fruit juices

Question 18

Desloratadine (clarinex) indications (2)

Answer 18

• allergic rhinitis

- chronic urticaria

Question 19

Levocetirizine (xyzal) indications (3)

Answer 19

• perennial allergic rhinitis
• seasonal allergic rhinitis
• Chronic idiopathic urticaria

Question 20

Pseudoephedrine is a ___ often included in 2nd gen H1 blockers under the suffix ___

Answer 20

decongestant, -D

Question 21

1st line of drugs for patients with mild to moderate symptoms (2 things)

Answer 21

Antihistamine

Nasal corticosteroid

Question 22

This drug class is most effective at preventing and treating seasonal allergic rhinitis. What is the one big concern with children using this class?

Answer 22

Intranasal corticosteroids, stunted growth rate concerns

Question 23

Mast cell stabilizers mech of action

Answer 23

Inhibit release of histamine and other mediators of inflammation from sensitized mast cells as preventative measure

Question 24

Intranasal cromolyn (Nasalcrom) drug class, who is it primarily recommended for?

Answer 24

Nasal mast cell stabilizer, young children, pregnant, and elderly because it is very safe but only moderately effective

Question 25

Sympathomimetics mech of action

Answer 25

Decongestants through stimulating a1 adrenergicc receptors on nasal blood vessels resulting in vasoconstriction and shrinkage of swollen membranes followed by nasal drainage breaking up mucus

Question 26

Sympathomimetics nasal vs PO administration

Answer 26

Intranasal results in rapid intense action, PO is delayed but prolonged response

Question 27

Rhinitis medicamentosa

Answer 27

Rebound congestions resulting from down regulation of a adrenergic receptors when prolonged repeated use of intranasal decongestants occurs, requiring limitation of 3-5 days of use of intranasal decongestants, occurs orally as well requiring slow withdrawal to prevent sharp increase in congestion

Question 28

Sympathomimetics ADRs (3)

Answer 28

• rebound congestion
• CNS stimulation
• cardiovascular effects raising blood pressure and heart rate slightly

Question 29

Nasal saline

Answer 29

Drops and sprays used to relieve dryness and congestion

Question 30

Ipratropium bromide (atrovent nasal spray) mech of action

Answer 30

Anticholinergic agent that decreases mucus secretions

Question 31

Who is recommended to use Ipratropium bromide (atrovent nasal spray)

Answer 31

-Those who have watery rhinorrhea as a main complaint, otherwise no effect on congestion, sneezing, or itching

Question 32

Ipratropium bromide (atrovent nasal spray) ADR’s )2_

Answer 32

• Transient nasal dryness

- Bleeding

Question 33

Omalizumab(Xolair) mech of action

Answer 33

Composed of monoclonal antibodies directed against IgE preventing release of inflammatory mediators from mast cells and basophils

Question 34

What is omalizumab (xolair) used to treat

Answer 34

Assist albuterol or another asthma medication to alleviate symptoms of an attack