OTC Allergy and Insomnia

Question 1

what do allergies include? (5)

Answer 1

hay fever, food allergies, atopic dermatitis, allergic asthma, anaphylaxis

Question 2

what are the symptoms of allergies?

Answer 2

red eyes, itchy rash, sneezing, runny nose, shortness of breath or swelling

Question 3

what immunoglobin does allergies include?

Answer 3

IgE antibodies

Question 4

what are IgE antibodies produced by and why?

Answer 4

B cells; in response to an allergen/antigen

Question 5

what do IgE antibodies bind to?

Answer 5

receptors on mast cells or basophils (next exposure releases histamine)

Question 6

what kind of receptors are histamine receptors?

Answer 6

GPCRs (q - phospholipase C)

Question 7

what histamine receptor plays a predominant role in allergy response?

Answer 7

H1 (acute immune response)

Question 8

where are H1 receptors? (4)

Answer 8

smooth muscles, vascular endothelial cells, heart, CNS

Question 9

what does activation of the H1 receptor cause? (5)

Answer 9

incr vascular permeability, vasodilation, cough, smooth muscle contraction of bronchi, eosinophil chemotaxis

Question 10

where are histamine receptors concentrated in the brain?

Answer 10

regions controlling waking/arousal: thalamus, cortex, noradrenergic, serotonergic, dopaminergic nuclei)

Question 11

histamine is an important NT in the….

Answer 11

wake-promoting system

Question 12

what is diphenhydramine?

Answer 12

inverse agonist at H1 receptor (blocks activity)

Question 13

what does diphenhydramine do? (2)

Answer 13

blocks effects of histamine in blood vessels and smooth muscle cells to decr allergic rxn symptoms, suppresses medullary cough center

Question 14

what are first generation antihistamines?

Answer 14

first developed drugs for allergies

Question 15

how does diphenhydramine cause drowsiness?

Answer 15

crosses BBB and inversely agonizes CNS H1 receptors

Question 16

what is diphenhydramine marketed as? (3)

Answer 16

Benadryl (OTC allergy drug), Nytol (OTC sleep aid), Tylenol Cold and Flu (OTC Cough and Cold)

Question 17

what is the effect first gen antihistamines being non-selective?

Answer 17

cause off-target side effects

Question 18

what is an antagonists/inverse agonists affinity described by?

Answer 18

inhibitory constant (Ki)

Question 19

what is Ki?

Answer 19

[drug] that displaces 50% of labelled ligand (low Ki = high aff)

Question 20

what off-target receptors can first gen antihistamines bind to (not H1)?

Answer 20

muscarinic cholinergic receptors

Question 21

what are the off-target anticholinergic effects of antihistamines?

Answer 21

dry mouth, constipation and confusion (not recommended for older individuals)

Question 22

what are 3 cons of diphenhydramine?

Answer 22

tolerance develops rapidly to sedative effects, decr sleep quality, long-term association w/ Alzheimers (anticholinergic effects)

Question 23

what is different btwn first and second gen antihistamines? (3)

Answer 23

more selective for H1 receptors, poor BBB permeability (lack sedative effects), longer duration of action (decr doses)

Question 24

what is cetirizine?

Answer 24

H1 receptor antagonist

Question 25

what is the duration of action of cetirizine?

Answer 25

24 hrs (diphenhydramine: 4-6 hrs)

Question 26

what is loratidine?

Answer 26

H1 inverse agonist

Question 27

what is the issue with loratadine?

Answer 27

almost entirely bound to plasma proteins (not active)

Question 28

what occurs when loratidine is given orally?

Answer 28

rapid first pass metabolism converts it to desloratadine (loratadine: prodrug)

Question 29

what does desloratadine do?

Answer 29

has anti-histamine effects (poor penetration of BBB, weakly sedating)

Question 30

what is the difference btwn loratadine and desloratadine half-life?

Answer 30

incr half-life (8 vs 27 hrs)