antihistamines

Question 1

cause of allergies

Answer 1

IgE located on mast cells in tissues and basophils in blood

first exposure – develops IgE
second exposure – hypersensitivity response

Question 2

what is histamine

Answer 2

substance released when there is tissue damage, inflammation and allergic rxn

Question 3

types of histamine receptors

Answer 3

H1 allergic inflammation
H2 gastric acid secretion
H3 neurotransmission
H4 immunomodulation

Question 4

antihistamine mode of action?

Answer 4

competitive H1 receptor antagonist

Question 5

adverse drug rxns of 1st gen antihistamines

Answer 5

crosses BBB and have anti-cholinergic activities
- sedation
- dizziness
- blurred vision bc of mydriasis (dilated pupil)

2/3rd gen antihistamines are more selective for peripheral histamine receptors and have less severe side effects

Question 6

diphenhydramine

Answer 6

1st gen

Question 7

(dex)/chlorpheniramine

Answer 7

1st gen

Question 8

triprolidine

Answer 8

1st gen

Question 9

promethazine

Answer 9

1st gen

Question 10

hydroxyzine

Answer 10

1st gen

Question 11

cetirizine

Answer 11

2nd gen

Question 12

fexofenadine/telfast

Answer 12

2nd gen

Question 13

loratadine

Answer 13

2nd gen

Question 14

levocetirizine

Answer 14

3rd gen

Question 15

desloratadine

Answer 15

3rd gen

Question 16

phensedyl

Answer 16

OTC drug, brown mixture

• codeine (cough suppressant), metabolised to morphine
• promethazine (1st gen AH)

Question 17

polaramine expectorant

Answer 17

OTC drug

• dexchlorpheniramine (1st gen AH)
• guaiphenesin (expectorant)
• pseudoephedrine (vasoconstrictor, nasal decongestant), also indirect adrenergic