AR- Oral Antihistamines

Question 1

1st generation OAH

Answer 1

Chlorpheniramine
Diphenhydramine

Question 2

2nd generation OAH

Answer 2

Cetirizine
Levocetirizine
Loratadine
Desloratadine
Fexofenadine

Question 3

OAH MoA

Answer 3

Competitively antagonizes histamine-1 receptors to prevent receptor activation

Question 4

Properties of 1st generation OAHs

Answer 4

lipophilic, cross BBB, ACh effects and excessive sedation

Question 5

Properties of 2nd generation OAHs

Answer 5

highly selective for H1 receptor, limited penetration into CNS

Question 6

OAH symptom targets

Answer 6

Minimal congestion
Rhinorrhea
Sneezing
Nasal itching
Ocular symptoms

Question 7

OAH ADEs

Answer 7

Sedation, ACh side effects, change in appetite and GI discomfort

Question 8

Which generation of OAHs have a more favorable ADE profile?

Answer 8

2nd generation

Question 9

2nd generation OAHs that are the most sedating

Answer 9

cetirizine and levocetirizine

Question 10

When are OAHs most effective?

Answer 10

Administered prior to allergen exposure

Question 11

Cautions with 1st gen OAHs

Answer 11

Elderly patients
Use of other CNS depressants or ACh agents
Urinary retention issues/BPH
Slowed GI motility
Narrow-angle glaucoma
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