OTC Cough and Cold

Question 1

what do common OTC contain singly or a combination of? (4)

Answer 1

decongestant, cough suppressant (antitussive), expectorant and antipyretic

Question 2

what do OTC cough and cold medications usually treat?

Answer 2

upper respiratory infections (runny nose, congestion, cough, fever)

Question 3

what is the cough reflex?

Answer 3

reflex to clear breathing passage of irritants, microbes, fluids and mucus

Question 4

what is the cough reflex a common symptom of? (4)

Answer 4

upper respiratory tract viral or bacterial infections, asthma, bronchial irritation, etc.

Question 5

what is the cough reflex initiated by?

Answer 5

stimulation of sensory nerves in throat and lungs (eg. P2X3, TRPV1)

Question 6

where do sensory neurons send “cough info” to?

Answer 6

medulla oblongata (cough center in brain stem)

Question 7

what do efferent nerves (parasymp. and motor) stimulate in the cough reflex?

Answer 7

diaphragm, intercostal muscles and lungs to initiate “noisy expiration”

Question 8

what are drugs that inhibit cough reflex called?

Answer 8

antitussives

Question 9

how do most OTC antitussives work?

Answer 9

inhibit neurons in medulla oblongata

Question 10

how effective are antitussives at reducing cough in clinical trials?

Answer 10

only moderately effective (not much better than placebo)

Question 11

what is codeine?

Answer 11

mu opioid receptor agonist

Question 12

where are mu opioid receptors found?

Answer 12

medulla oblongata (cough center) and peripheral nerves in respiratory tract

Question 13

what are mu opioid receptors?

Answer 13

inhibitory GPCRs

Question 14

how does activation of opioid receptors affect neuronal activity? (3)

Answer 14

inhibit of Ca channels, activate of K channels, and inhibit of adenylyl cyclase ie. neuronal inactivation and decr NT release

Question 15

what are the effects of codeine?

Answer 15

arrests cough response (efferent) and decr respiration

Question 16

what are 2 serious side effect of codeine?

Answer 16

addiction, overdose (death)

Question 17

what was low dose codeine mixed with?

Answer 17

Tylenol 3s

Question 18

what is dextromethorphan?

Answer 18

centrally active NMDA receptor antagonist

Question 19

how are dextromethorphan and codeine similar and different?

Answer 19

sim: inhibit neurons in medulla oblongata
diff: dex-antagonist, cod-agonist

Question 20

what is diphenhydramine?

Answer 20

antihistamine (H1 inverse agonist~antagonist)

Question 21

what H1 receptors?

Answer 21

Gq coupled receptors

Question 22

where are H1 receptors?

Answer 22

respiratory smooth muscles

Question 23

what do H1 receptors stimulate?

Answer 23

sensory nerves producing cough

Question 24

what does diphenhydramine binding to H1 receptors cause?

Answer 24

inhibits histamine action and receptor action

Question 25

what does histamine binding to H1 receptors cause?

Answer 25

in resp. tract - coughing

Question 26

what allows diphenhydramine to inhibit cough reflex in medulla oblongata?

Answer 26

can cross BBB (blood brain barrier)

Question 27

what do decongestants do?

Answer 27

decr nasal congestion, edema (swelling) of nasal passage, decr tissue hyperemia, etc.

Question 28

what is pseudoephedrine?

Answer 28

agonist for a and B adrenergic receptors (sympathomimetic drug-mimics noradrenaline)

Question 29

what does activation of a adrenergic receptors by pseudoephedrine cause?

Answer 29

vasoconstriction of blood vessels in mucosa of resp. tract

Question 30

what does activation of B adrenergic receptors by pseudoephedrine cause?

Answer 30

smooth muscle relaxation and vasodilation (bronchi)

Question 31

what is pseudoephedrine structurally similar to?

Answer 31

amphetamine (stimulant)

Question 32

what is phenylephrine?

Answer 32

specific a adrenergic receptor agonist

Question 33

what does phenylephrine binding to a adrenergic receptors cause?

Answer 33

vasoconstriction in nasal mucosa (no bronchial relaxation or HR incr) - less effective

Question 34

what are expectorants?

Answer 34

oral drugs that incr mucus clearance

Question 35

what expectorant was not removed from the market in the 90s by the FDA/Health Canada?

Answer 35

Guaifenesin (Mucinex)

Question 36

where was guaifenesin discovered by indigenous communities?

Answer 36

bark of Guaiac tree

Question 37

how does guaifenesin work?

Answer 37

incr expulsion of bronchial secretion by dec adhesiveness and surface tension of mucus

Question 38

what is theorized to be the mechanism of action of guaifenesin? (not actually known)

Answer 38

irritate gastric vagal receptors that recruit efferent parasymp. reflexes causing glandular exocytosis of less viscous mixture

Question 39

Why is codeine not recommended for individuals under 18 y/o?

Answer 39

Children are at higher risk for on-target effects leading to respiratory depression