Antihistamines Flashcards
Autacoids
Local and sometimes systemic regulators of blood flow and inflammatory process
What class of autacoids are we studying
Decarboxylated amino acids
Where is histamine made
mast cells, basophils, ECL in GI mucosa, neurons of CNS
Metabolism of histamines
Oxidative pathway in liver
What sensitivity does histamine play a role in
IgE mediated type I
What kind of drug is cisapride
5HT4 and enhance Ach release
What kind of drug is mirtazipine
Atypical antidepressant- blocks 5HT2a, 2c, alpha2
What kind of drug is fluoxetine
SSRI
What kind of drug is Clomipramine
TCA
What kind of histamine is meclizine
H1 1st gen
What kind of histamine is cyproheptadine
H1 1st gen
What kind of histamine is diphenhydramine
H1 first gen
What kind of drug is selegeline
Selective MAOb (at higher MAOa as well)
What kind of histamine is famotidine
H2
What kind of drug is trazodone
5HT2a/2c and weak PreSRI
What kind of drug is ondansetron
5HT3 antagonist
First gen vs second gen
1st less selective, cross BBB (drowsiness)
Diphenhydramine - metabolism
liver, metabolites excreted by urine
Diphenhydramine - uses
Anti-emetic, rhinitis, pruritis, allergic derm
Cyproheptadine- uses
cat app stim, serotonin syndrome in dogs
Meclizine- uses
Motion sickness and anti-emetic, vestibular disorders in dogs; CRTZ
Function of H2
gastric secretion
Most potent, longest duration H2 blocker
Famotidine
Famotidine- metab
Liver, first pass substantial, unchanged in urine
Where is 5HT found
Primarily in GI tissue, some in CNS, platelets
Serotonin syndroms- cause/effect
Altered serotonin via 5HT receptor- temperature and hemdynamic changes
What mediates serotonin degradation
MAO
Selegeline- MOA
selective MAOB
Selegeline- uses
Canine cognitive dysfunction, cushings
Selegeline- SE
GI, CNS excitation or lethargy
TCA- example
Clomipramine
Common SE of fluoxetine
Appetite reduction/weight loss
Mirtazipine- MOA
Blocks 5HT2a/2c, a2’s, increase NE transmission
Mirtazipine- uses
appetite stim, anti-emetic
Trazodone- MOA
Inhibits 5HT2a/2c and weak pre-synaptic SRI
Trazodone- uses-
Anxiolytic,
Cisapride- MOA
5HT4 agonist with Ach release
Cisapride- uses
Gastric motility, megacolon,
Ondansetron- uses
anti-emetic dogs
Ondansetron- MOA
CRTZ action via 5HT3