Shared Flashcard Set

Details

Antihistamines
Antihistamines
40
Medical
Professional
04/04/2011

Additional Medical Flashcards

 


 

Cards

Term
Large numbers of mast cells are located in the...(3)
Definition
Skin
Nasal mucosa
Lungs
Term
Histamine is also synthesized in ___ and acts as ___.
Definition
Non-mast cells of gastric mucosa and epidermis
Acts as an NT in the CNS
Term
Histamine exerts an ___ in ___.
Definition
Anabolic effect
Growth and repair
Term
Inhibition of ___ doesn't affect the degradation of histamine
Definition
MAO
Term
Some ___ contain histamine.
Definition
Insect venoms
Term
Re-exposure to the offending Ag causes ___ on ___, which results in ___
Definition
IgE bridges form
Surface of the mast cell
Increased intracellular Ca and degranulation
Term
Something released from mast cells elicits ___
Definition
De novo synthesis of bronchoconstrictors PGD2, LTC4, and LTD4 (LTC and LTD are the slow-reacting substances of anaphylaxis)
Term
The majority of the inflammation and tissue damage caused by mast cell degranulation is actually ___, which explains why antihistamines ___
Definition
Mediated by compounds other than histamine
Antihistamines are only partially effective in reversing the inflammatory reactions involved in hypersensitivity
Term
It's better to ___
Definition
Prevent degranulation
Term
___ producing ___ of mast cells also causes histamine release.
Definition
Mechanical injury producing destruction of mast cells
Term
Ag-induced histamine release (mast-cell degranulation) is inhibited by (2), MOA
Definition
Cromolyn sodium
Olapatadine

Both prevent the increase in intracellular Ca caused by IgE cross-bridging
Term
See the chart on p. 346 for the role of histamine in the secretion of gastric acid.
Definition
Term
H1R second messenger system effects (5)
Definition
IP3

On arteriolar endothelium: synthesizes NO => hypotension and reflexly-mediate tachycardia (fast onset and offset)
Sensory nerve endings: pain, itching
Contraction of:
-Postcapillary venule endothelial cells => extravasation of plasma => local edema
-Bronchial smooth muscle => decreased ventilation, FEV1, PEFR
-GI smooth muscle => enhanced peristalsi => cramping, involuntary defecation
Term
H2R second messenger system, effects (2)
Definition
Adenyl cyclase

Arteriolar VD => hypotension (slow onset and offset)
Parietal cell: increased acid secretion
Term
Triple response of Lewis
Definition
Flush: histamine => VD => localized red spot at site of injury w/in a few seconds

Flare: histamine => axonal reflexes in sensory nerves => surrounding blood vessel VD => diffuse flush extending 1cm around site of injury, appears more slowly

Wheal: histamine => increased capillary permeability => edema localized at site of injury, several minutes
Term
Stimulate sensory nerve endings to cause sensations of pain, itching, and burning = algesia (3)
Definition
Histamine
PG
Bradykinin
Term
Immediate hypersensitivity reaction, drugs (2)
Definition
Bronchoconstriction => severe dyspnea

DOC bronchoconstriction is subcu EPI
Tx hypotension: H1 + H2 blockers = diphenhydramine + cimetidine
Term
Gastric/duodenal ulcer: pathophysiology
Definition
Stimulation of H2R
Increased acid secretion
Promotes/exacerbates ulceration and can cause stress ulcers like in severe trauma (burns)
Term
Cromolyn sodium: indications (3) and method of admin (4)
Definition
Asthma: inhaler
Allergy: eyedrops, nasal spray
Food allergy: oral
Term
Olopatadine: indication, method of admin, also blocks...
Definition
Allergy: eyedrops

Also blocks H1R
Term
H1R antagonists = antihistamines (13)
Definition
brompheniramine
cetirizine
chlorphenirmaine
cyproheptadine
desloratadine
dimenhydrinate
diphenhydramine
fexofenadine
hydroxyzine
loratadine
meclizine
olopatadine
promethazine
Term
Most antihistamines are prego class ___ except HOP (3)
Definition
B

C:
-Hydroxyzine
-Olopatadine
-Promethazine
Term
Most antihistamines are sedating except (4?)
Definition
Cetirizine
Fexofenadine
Loratadine

?Olapatadine?
Term
If an antihistamine is sedating it's also ___.
Definition
Anti-emetic
Term
The least sedating/anti-emetic of the sedative antihistamines are (3)
Definition
Brompheniramine
Chlorpheniramine
Cyproheptadine
Term
H1R blockade (both sedating and non-sedating antihistamines): effects (3)
Definition
Prevents bronchial and GI smooth muscle contraction
Inhibits pain and itching (sensory nerve endings)
Antagonizes the increased capillary permeability
Term
Muscarinic-R blockade (sedating antihistamines only): effects (4)
Definition
Depress CNS
Inhibit nasopharyngeal secretion
Prevent motion sickness (vestibular nuclei)
Anti-emetic
Term
Topical diphenhydramine: specific effect, MOA
Definition
Local anesthesia

Blocks Na channels in afferent sensory pain fibers
Term
H1R blockers: indications (7)
Definition
Seasonal and allergic rhinitis
Acute hypersensitivity adjunct tx
Motion sickness
Pre-op sedation
N/v
Vertigo
Parkinson's

Don't use in serous otitis media!
Term
Motion sickness: drugs (3)
Definition
Prophylaxis: dimenhydrinate
Diphenhydramine
Meclizine
Promethazine
Term
Pre-op sedation: drug
Definition
Promethazine
Term
Vertigo (spontaneous bursts of semicircular canal activity): drugs, effects (2)
Definition
Dimenhydrinate
Meclizine

Reduce the nausea, ataxia, nystagmus
Term
Parkinson's: drug, effect
Definition
Diphenhydramine

Treat central motor disorder caused by the antipsychotics
Term
Promethazine: method of admin (2), indications (6)
Definition
IM (not IV!)
Rectal suppository

Acute hypersensitivity
Allergic dermatoses
Motion sickness
Sedate anxious patients
Prevent post-op n/v
Tx n/v associated with GI infection
Term
H1R blockers: S/E
Definition
CNS depression: decreased alertness, slowed reaction times, somnolence (potentiates CNS depression caused by other depressants)
CNS excitation: paradoxical, with overdose
Dizziness, tinnitus
Antimuscarinic (esp. in older patients): dry mouth and respiratory tract, urinary retention if have BPH, exacerbation of glaucoma
Term
H2R blockers (3)
Definition
Cimetidine
Famotidine
Ranitidine
Term
H2R blockers: effect (2)
Definition
Inhibit basal and nocturnal acid secretion
Inhibit secretion of gastric acid induced by things like food, coffee, insulin, muscarinic agonists, increased vagal nerve activity, histamine agonists, and gastrin
Term
H2R blockers: indications (5?)
Definition
Gastric/duodenal ulcers
GERD
Prophylaxis for stress ulcers
Anaphylaxis

?Viral warts?
Term
H2R blockers: S/E (3)
Definition
Prego B
n/d
Skin rash
Term
Cimetidine: S/E (3)
Definition
Inhibits P450
-Can't breakdown estrogen => anti-androgenic effects
-Increases the t1/2 of things like B-blockers, warfarin, diazepam

CNS effects: mental confusion to over psychosis in older patients/prior hx psych disease/large doses for long period
Supporting users have an ad free experience!