Anti-Histamines

Question 1

H1 receptors involved in

Answer 1

Acute allergic reactions (Gq receptors), adrenal/salivary/pancreas/bronchial secretion, arterial relaxation, venous/bronchiolar/uterine/GI contraction

Question 2

H2 receptors involved in

Answer 2

Gastric acid secretion (Gs receptors), positive chronotropy/ionotropy

Question 3

H3 receptors involved in

Answer 3

Neurotransmitter modulation (Gi receptors)

Question 4

H4 receptors involved in

Answer 4

Immunomodulator

Question 5

First gen H1 antagonist MOA

Answer 5

Diphenhydramine, chlorphenamine, promethazine reduce inflammation/allergic response by blocking H1 receptors and can cross blood brain barrier

Question 6

First gen H1 antagonist (can cross blood brain barrier) SE

Answer 6

Drowsiness (but still used in children for this effect), dizziness, tinnitus, fatigue

Question 7

Second gen H1 antagonist MOA

Answer 7

Fexofenadine, cetirizine, loratidine, astemizole, terfenadine block H1 like 1st gen but can’t cross blood brain barrier

Question 8

H2 antagonists use

Answer 8

Cimetidine and ranitidine formerly used in GI ulcer treatment but superceded by PPI