Dr.Joshi Anti-histamtic drugs

What are the 3 major sites of storage for Histamine

Mast cells in skin, respiratory tract and intestine

What triggers the release of histamine

Antigens
allergens

chemicals/drugs,

What are the 6 allergic phenomenas?

 Hypersensitive reactions

 Urticaria

 Angioedema

 Bronchoconstriction

 Vasodilation

 Anaphylactic shock may lead death

histamine 1 2 3 and 4

• H1 = Allergies and sleep disorder

• H2 =Gastric Acid secretion

• H3 = CNS disorder

• H4 = Inflammation disorder

What receptor type are all 4 histamines?

GPCR

What are the Aminoalkyl Ethers drugs and what generation?

GEN 1
———————-
Diphenhdramine
Doxylamine
Clemastine
Dimenhydrinate

What are the Alkylamines drugs and what generation?

Gen 1
———————-
Chlorpheniramine
,Brompheniramine,
Dexbrompheniramine,
Dexchlorpheniramine ALL AMINES EXEPT DOXY AND DIPEN and trip
Triprolidine

What is the Phenothiazines drug and what gen?

Gen 1
_____________
Promethazine

what are the Piperazines drugs and classify gen 1 vs 2

Gen 1
—————
Meclizine
Hydoxyzine MAX HATES GEN 1
Gen II
___________
Cetirizine Carie loves gen 2
Levocetirizine.

What is the Piperidines drugs and what classify by generation

Gen 1
——————-
Cyproheptadine
Gen II
——————
Loratadine
Desloratadine
Fexofenadine

What drug is a phthalazine derivative and has a better topical activity?

Azelastine

What gen is Azelastine

Gen II

What drug is A dibenzoxepines that works with dual mechanism, antihistamine and is a mast-cell stabilizer? and what Gen?

Olopatadine
gen II

____-generation H1 antihistamines are lipophilic, cross the BBB and sedative

First

_____-generation H1 antihistamines are hydrophilic, cross the BBB to a lesser extent, and non-sedative with selective peripheral effects

Second

First gen anti-histamine side effects

Dry mucous membrane
restlessness
ataxia
hyperthermia,

hypertension
Sedative
drowsiness
diminished alertness
Motor incoordination-pt should not operate motor veichle
fatigue
Anticholinergic effect, such as dry mouth, alteration of bowel movement, urinary retention, blurring of vision

Higher dose and longer use of diphenhydramine and loratadine may also lead to?

Prolonged qt

Hydroxyzine and fexofenadine, are associated with _______ effects in animal study

teratogenic

Most antihistamines are category b which of the following are category c

hydroxyzine,
fexofenadine,
azelastine
olopatadine

Which anti-histamtimes are CYP3A4 substrates, should be avoided with its inhibitors

Chlorpheniramine,
cetirizine,
loratadine
fexofenadine

ntacids reduce the absorption of ________

fexofenadine