1-OTC allergy and sleep Flashcards
old anti-histamine example
diphenhydraine
new anti-histamine example
Loratidine
what is histamine and what do
local hormone in periphery to communicate between cells, neurotransmitter in CNS
where is histamine most present
tissues exposed to environment (skin, GIT, lungs)
where histamine released from and when
mast cells and basophil
inflammation and immune responses
what kind of drug is antihistamine (antagonist, agonist)
inverse agonist
why were first gen anti-histamines sedating
crossed the blood brain barrier
why could first gen anti-histamines cross the BBB
neutral at physiological pH
why are second gen anti-histamines non sedating
can’t cross BBB
why can’t second gen anti-histamines cross the BBB
charged at physiological pH and P-glycoproteins pump them out
what do P-glycoproteins do
pump out drugs, like second gen anti-histamines
are anti-histamines selective
yes between H1 and H2, but not against other similar receptors
H1 receptor
G protein, effector and 2nd messengers
Gq
PLC
IP3, DAG mostly NO
what does NO do in cell
vasodilate
H2 receptor
G protein, effector and 2nd messengers
Gs
AC
cAMP
gastric acid release
3 main responses of H1 receptor activation
edema, sensitization of other receptors, vasodilation
antagonist to H1 receptor
ADRENALINEEEE (epipen)
wheal and flare
wheal middle where lots of sweling, flare is sides with redness
which antibody production is associated to allergies
IgE
common structure of gen 1 H1 antihistamines
2ar-X-c-c-N=
x is either
c=o
n
common feature of gen 2 H1 antihistamines
all have carboxyl group that gets - at physiological pH
more structurally diverse
which gen is more H1 selective and why
gen 2
their - charge makes them bind stronger to the + pocked
why are gen 1 H1 antihistamines bad for blood pressure
blocks adrenergic receptors, causes low blood pressure because adrenaline can’t bind to it and they stay dilated (α adrenergic cause vasoconstriction)
how do H1 antihistamines affect sleep
lots of H1 receptors found in areas that must be activated for wakefulness, blocking it makes you sleep
they also affect circadian rhythm
what is the tuberommammillary nucleus
where all histamine releasing neurons originate
