Week 6: Allergy Medications

Question 1

Diphenhydramine (Benadryl) indications

Answer 1

• allergic rhinitis
• hypersensitivity reactions
• urticaria and angioedema
• insomnia

Question 2

Diphenhydramine Drug Class

Answer 2

1st Generation Antihistamine

Question 3

Diphenhydramine MOA

Answer 3

• competitively antagonized the effects of histamine at the H1 receptor sites - has anticholinergic effects

Question 4

Diphenhydramine Cautions/ Contraindications

Answer 4

• crosses the blood-brain barrier
• not to be combined with CNS depressants
• avoid in patients with glaucoma, BPH d/t anticholinergic effects
• avoid in infants, newborns, elderly
• Safe in pregnancy
• avoid in lactation (dries up milk production)

Question 5

1st Generation Antihistamines (Benadryl) ADRs

Answer 5

• sedation - dizziness - confusion - ataxia - urinary retention - paradoxical excitation - dry mouth - tremor - blurred vision - constipation (think anticholinergic effects and CNS effects)

***cross the blood-brain barrier***

Question 6

2nd Generation Antihistamines Examples

Answer 6

Cetirizine (Zyrtec) Loratadine Fexofenadine

Question 7

2nd Generation Antihistamine (Zyrtec/ Loratadine/ Fexofenadine) indications

Answer 7

• respiratory allergies - urticaria

Question 8

2nd Generation Antihistamine MOA (Zyrtec/ Loratadine/ Fexofenadine)

Answer 8

• competitively antagonizes the effects of histamine at the peripheral H1 receptor sites in the GI tract, blood vessels, and repiratory tract - in general- avoids crossing the blood-brain barrier - no anticholinergic effects

Question 9

2nd Generation Antihistamines - Cetirizine, Loratadine, Fexofenadine cautions/ contraindications

Answer 9

• safe in pregnancy and lactation
• may have some CNS effects and can cause drowsiness - not as much as with 1st gen.
• Cetirizine ok for 6mo and older
• Loratadine ok for > 2 year olds
• Fexofenadine ok for > 6 year olds