Histamine is a complex amine that has 4 receptors with multiple physiologic pathways. Describe the main differences in action between H1 and H2 histamine receptors.
H1 : Vasodilation, bronchochonstriction, cellular migration, nociception, CNS excitation. H2 : gastric acid secretion, vascular permeability, and airway mucous
What chemical attribute of H1 antagonists allows them to cross the BBB?
Lipophilicity (lipid soluble) and very small chemical structure
What is anaphylaxis on a pathophysiologic level?
A large amount of IgE binding to mast cells, release a large quantity of histamine and other inflammatory mediators. hypotension + bronchocon.
Adrenaline is a physiologic antagonist to anaphylaxis. Why not use JUST H1 antihistamines as a receptor antagonist?
Long Onset of action, might be dead already. May not just be from histamine mediation, possibly also cytokines and eicosanoids.
When is it appropriate to just use H1 antihistamine for a reaction?
Hypersensitivity reactions from vaccinations (esp when given with glucocorticoids). Less intense and longer duration of action than adrenaline.
Why should we not give H1 antihistamines via IV?
CNS EXCITEMENT!! Can cause immediate seizures and excitability of CNS, as well as a rapid sedation effect
H1 Antagonists First generation is:
Chlorpheniramine. Important to help lower corticosteroid doses in chronic atopy, as well as allergies. Crosses BBB
H1 Antagonists Second generation is:
Cetirizine. Less lipophilicity, less BBB action, no on-label use yet.
Pruritis has been connected to one interleukin in particular. Which one is it?
IL-31! Message sent to the brain which is interpreted as itchiness
I'm a Janus kinase inhibitor. I can help sooth that intractable itch, but won't find the cure. You might like to use me when glucocorticoids aren't a good option, but NEVER with!
Oclacitinib
What does vetmab stand for?
Veterinary monoclonal antibody
Like my well known friend, I too can help your itchy pooch. Except I'm better, faster, stronger (fewer SE). I help with canine atopy and pyoderma too! You get me as a powder, but once I'm reconstituted I can work wonders for up to a month
Lokivetmab
