Antihistamines

Question 1

common uses for antihistamines

Answer 1

allergies
pruritis
urticaria
N/V
anaphylaxis

Question 2

mechanism behind allergic rxns

Answer 2

upon initial exposure to antigen, body creates IgE antibodies which, on secondary exposure, stimulate the activation of H1 receptors w/histamine causing:
runny nose
sneezing
itchy eyes
itchy rash
vasodilation

Question 3

antihistamine meds

Answer 3

1st gen H1 blockers: cross BBB–>drowsiness!
diphenhydramine
promethazine
hydroxyzine

2nd gen H1 blockers: decreased lipid solubility
loratadine
cetirizine
fexofenadine
desloratadine

Question 4

mechanism of action for antihistamines

Answer 4

block H1 receptors, decreasing the effects of histamine

Question 5

adverse effects for antihistamines

Answer 5

1st gen H1 blockers:
sedation
anticholinergic

2nd gen H1 blockers:
well-tolerated
longer duration