Antihistamines

Question 1

What are the first generation antihistamines?

Answer 1

Die Die Chris Hanson: Diphenhydramine, Dimenhydrinate, Chlorpheniramine, Hydroxyzine

Question 2

What are the theraputics of the first generation antihistamines? (Hint: CAIM)

Answer 2

1. Contact flora
2. Asthma/hay fever
3. Insect stings
4. Motion sickness

Question 3

What are the adverse drug effects of 1st generation antihistamines? (Hint: H-MASK)

Answer 3

1. H1 receptors: decrease CNS –> sedation
2. Musc: urinary retention, tachycardia, xerostoma
3. Alpha: hypotension, reflex tachycardia
4. Serotonin: increased appetite
5. K current: QT prolongation (like the FQ’s and macrolides

Question 4

Which 1st generation antihistamine is the longest acting?

Answer 4

Hydroxyzine

Question 5

Which antihistamines are the strongest sedatives and also act as anticholinergics?

Answer 5

Diphenhydramine and Dimenhydrinate

Question 6

What are the 2nd generation antihistamines?

Answer 6

Fexofinadine and Cetirizine (they had to CET and FEX the 1st generation!)

Question 7

What is the biggest differences in the 1st and 2nd generation of antihistamines?

Answer 7

The 2nd generation has less ADE’s. The do not cross the BBB thus no sedation and they are not anticholinergic

Question 8

What are the activators of histamine synthesis and release? (name 4)

Answer 8

1. Inflammatory cytokines (ILs, PGs, GM-CSF)
2. Endotoxin (from bacterial infection) and Vanc
3. Gastrin
4. IgE

Question 9

Name 2 inhibitors of histamine synthesis/release

Answer 9

1. H1 antagonists (duh)

2. B-adrenergics

Question 10

Which generation of antihistamines has a longer duration?

Answer 10

2nd generation