anti-histamine Flashcards
When is histamine released normally? (2)
- secretion of gastric juice
- immune response
What are the pathologival processes in which histamine is released? (3)
- inflammatory reactions
- temperature changes
- immediate hypersensitivity reactions
H1 receptor is found in … (4)
- smooth muscle cells of blood vessels
- bronchi
- digestive
- skin
H2 receptor is found in …
parietal cells of gastric mucosa
H3 receptor is found in …
CNS
H4 receptor is found in … (5)
- hematopoietic cells
- eosinophils
- mast cells
- bone marrow
- gastrointestinal tract
define hypersensitivity
reaction to a foreign substance (allergen)
What cells mediate the immune response in hypersensitivity reactions?
- eosinophils (blood)
- mast cell (tissue)
*release histamine
Which cells release histamine?
mast cells
eosinophils
What are the direct effects of histamine? (3)
- vasodilation
- bronchoconstriction
- activation of infammatory cascasde
What is the mechanism of action for histamine?
stimulates specific receptors
H1 receptors effects? (6)
- smooth muscle cells of blood vessels: vasodilation + incr. permeability
- bronchi: bronchoconstriction
- digestive: spasms
- skin: pain + pruritus
H2 receptor effects?
increased secretion of H+
Mechanism of action for antihistamine H1
-antagonist for H1 receptors
When do antihistamine H1 adverse reactions occur? what are the effects? (3)
- when it antagonizes other receptors
- sedative (CNS)
- anticholinergic (Ach)
What pharmacologic effects do anti-histamines H1 have? (6)
- sedative
- hypnotic
- anti-motion sickness
- anticholingeric
- antiserotonin
- h1 antagonist
Describe 1st generation anti-histamine H1’s (2)
- very potent
- cross BBB (therefore sedation)
Describe 2nd generation anti-histamine H1’s (2)
- moderate effect
- do not cross BBB
anti-histamine H1 indications (3)
- allergies
- anti-motion sickness
- sedatives/hypnotics
Which antihistamine H1s are used for anti-motion sickness? (2)
- Dimenhydrinate (Biodramina®)
- Diphenhydramine (Soñodor®)
Which antihistamine H1s are used as sedatives and hypnotics? (2)
- Diphenhydramine (Soñodor®)
- Hydroxyzine (Atarax®)
How are anti-histamine H1s administered?
orally
anti-histamine H1 first pass?
liver
anti-histamine H1 metabolized in…?
liver
adverse reaction of anti-histamine H1 in adults? (2)
- cns: sleepiness
- anticholinergic effects: dry mouth, urinary retention, blurred vision
adverse reaction of anti-histamine H1 in children?
excitation
What is ebastine?
anti-histamine H1 2nd generation
2nd generation antihistamines have no _____ effects (2)
anticholinergic
sedative
the most used antihistamine H1 is ?
2nd generation
The second generation antihistamines are: (8)
CETIRIZINE EBASTINE LORATADINE FEXOFENADINE LEVOCETIRIZINE DESLORATADINE MIZOLASTINE RUPATADINE
