AH and H

Question 1

Name the antihistamines and compare and contrast

give PD for the comparison and give gen 1 AE

Answer 1

Gen 1

• Diphenhydramine - mix of H and M blocker for Vestibular Nu for motion sickness
• Promethazine - for sleep

Gen 2

• Loratadine
• Cetirizine
• Fexofenadine
• PSEUDOEPHEDRINE

Gen 1

• passes BBB
• sedation, psychomotor skill, dizziness;
• M blocker, alpha blocker, Serotonin blocker
• increases QTC interval, Ventricula arrythmia;
• Highly lipophilic, low molecular weight
• Low H1 specificity

PD:
- Gen 1 is slower onset and shorter MOA;

Question 2

Asthma give what

Answer 2

not Antihistamines

LABA and Fluticasone; formoterol

Question 3

Briefly describe the involvement of histamine in inflammation

• plus other functions of histamine

Answer 3

Allergy - mast cell - histamine
(note mast cell also releases heparin)

Inflammation - WBCs, also releases histamine

• Histamine mainly vasodilation; also increases membrane permeability; smooth muscle contraction for bronchoconstriction;
• Wake-promoting!!! hence promethazine for sleep
• itch

Question 4

Gimme 2 pathways of histamine production

Answer 4

WBC, Basophil, Mast cells
- by IgE or IgG

Gastrin stimulate ECL cells release Histamine to trigger parietal cell – H2

Question 5

anti-histamine MOA

- downstream effects

Answer 5

Inverse agonist

• stabilizes receptor in inactive form
• GPCR receptors
• downstream
• decreases expression of pro-inflammatory cytokines
• decrease itch
• mast cell stabilizer