antihistamines Flashcards
histamine receptors for our drugs are H_ and H_
1 & 2
bronchoconstriction comes from H_ , increased HR comes from H_
1, 2
through H1 and H2 receptors, histamine causes
___ cap permeability
____tension
_____Cardia
increased
hypo
tachy
T/F Increased capillary permeability leads to edema (wheal) and dilated arteries around the edema (flare).
TRUE
how do H1 and H2 balance each other in the lungs
H1 activation causes bronchial smooth muscle constriction
H2 activation relaxes bronchial smooth muscle
histamine leads to a more alkaline environment in the gut
FALSE. acidic
it evokes secretion of gastric fluid containing high concentrations of hydrogen ions, and vagal activity also increases H+ secretion.
histamine receptor antagonists are
competiive or non-competitive?
reversible or irreversible?
competitive and reversible.
T/F Histamine receptor antagonists inhibit the release of histamine, thus reducing its response.
FALSE
Histamine receptor antagonists do NOT inhibit the release of histamine, but rather attach to receptors and prevent the responses mediated by histamine.
histamine receptor antagonist stabilize the receptor in its____ form
active or inactive?
inactive
inverse agonist/antagonist
^same thing
H1 side effects:
first generation
CNS ____ (stim or dep?)
anticholinergic
CV: ___Cardia,
CNS depression (can have flipped in kids or elderly)
anticholinergic: dry mouth, blurred vision, urinary retention, constipation
CV: tachycardia, QT prolong, heart block, cardiac dys
what drug is a good choice for type 1 allergic reactions (anaphylaxis)
diphenhydramine (benadryl_
what drug is used to treat motion sickness and PONV
dimenhydrinate (dramamine)
It inhibits the integrative functioning of vestibular nuclei by decreasing vestibular and visual input
which drugs are second gen antihistamines
zyrtex/xyzal (cetrizine/levocetrizine)
claritin- loaratidine
allegra - fexofenadine
