Lecture 13 - OTC Cough and Cold

Question 1

commonly available over the counter cough and cold medications contain either singly or in combination a:

Answer 1

decongestant, cough suppressant, expectorant, and/or antipyretic/analgesic

Question 2

cough and cold medications are used to treat:

Answer 2

symptoms of upper respiratory infections

Question 3

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

Answer 3

coughing

Question 4

coughing is a common symptom of:

Answer 4

upper respiratory tract viral infections

Question 5

the coughing reflex is initiated by:

Answer 5

stimulation of sensory nerves innervating the throat and lungs

Question 6

sensory neurons in the throat and lungs send stimulatory information to the ______ in the ______

Answer 6

nucleus tractus solitarus (nTS), brainstem medulla oblongata

Question 7

efferent neurons via the _____ stimulate the diaphragm, intercostal muscles, and lungs to initiate a cough

Answer 7

parasympathetic and motor neurons

Question 8

over the counter drugs that inhibit the cough reflex (antitussives) do so mostly by:

Answer 8

inhibiting neurons in the nucleus tractus solitarus (nTS)

Question 9

what is codeine?

Answer 9

a mu opioid receptor agonist

Question 10

mu opioid receptors are located in the:

Answer 10

nucleus tractus solitarus (nTS) and peripherial nerves innervating the respiratory tract

Question 11

opioid receptors are:

Answer 11

inhibitory GPCRs (Gi-GPCR)

Question 12

activation of opioid receptors leads to:

Answer 12

inhibition of adenylate cyclase –> neuronal inactivation and reduced neurotransmitter release

Question 13

why is opioid use so dangerous?

Answer 13

opioid receptors are also located in the brainstem regions that mediate the breathing reflex (preBotzinger complex); high dose opioids inhibit the breathing reflex

Question 14

what is dextromethorphan?

Answer 14

a centrally active NMDA receptor antagonist

Question 15

what is the function of dextromethorphan?

Answer 15

inhibits neurons in the nucleus tractus solitarus (nTS)

Question 16

a ligand gated ion channel gated by glutamate

Answer 16

NMDA receptor

Question 17

how effective is dextromethorphan at treating a cough?

Answer 17

not very

Question 18

what is diphenhydramine?

Answer 18

an antihistamine (H1 inverse agonist)

Question 19

H1 receptors are:

Answer 19

Gq coupled GPCRs

Question 20

where are H1 receptors located?

Answer 20

respiratory smooth muscles

Question 21

inhibits histamine action at H1 receptors and crosses the blood brain barrier in the nucleus tractus solitarus (nTS)

Answer 21

diphenhydramine

Question 22

what is the most effective, but not dangerous, antitussive?

Answer 22

honey

Question 23

type of receptor located on vascular arterioles and cause vasoconstriction when activated

Answer 23

alpha-1 adrenergic receptors

Question 24

type of receptor located on vascular arterioles and veins, as well as broadly throughout the central nervous system

Answer 24

alpha-2 adrenergic receptors

Question 25

type of receptor located on the bronchioles and in the heart

Answer 25

beta adrenergic receptors

Question 26

alpha-1 adrenergic receptors are:

Answer 26

Gq coupled GPCRs

Question 27

alpha-2 adrenergic receptors are:

Answer 27

Gi couples GPCRs

Question 28

beta adrenergic receptors are:

Answer 28

Gs coupled GPCRs

Question 29

both alpha-1 receptors and alpha-2 receptors lead to:

Answer 29

smooth muscle contraction

Question 30

how is it that both alpha-1 and alpha-2 receptors can cause smooth muscle contraction?

Answer 30

- for alpha-1, activation of Gq proteins increase PLC and IP3 pathways; this stimulates the release of calcium and smooth muscle contraction - for alpha-2, inhibition of adenylate cyclase reduces cAMP, which increase MLCK activation and increases smooth muscle contraction

Question 31

what is pseudophedrine?

Answer 31

a non-specific agonist at the alpha and beta adrenergic receptors

Question 32

a drug that looks like an endogenous agonist, and produces effects similar to activation of the sympathetic nervous system

Answer 32

sympathomimmetic drug

Question 33

pseudopherine activates alpha adrenergic receptors in the mucosa of the respiratory tract leading to:

Answer 33

vasoconstriction of blood vessels

Question 34

pseudophedrine activity at beta adrenergic receptors causes:

Answer 34

smooth muscle relaxation leading to dilation of the bronchi and increased mucociliary clearance

Question 35

what are the overall effects of pseudophedrine?

Answer 35

shrinks swollen nasal mucous membranes, reduces tissue hyperemia, edema, and nasal congestion

Question 36

pseudophedrine is structurally related to _____ and has stimulant proterties

Answer 36

amphetamine

Question 37

what is phenylephrine?

Answer 37

a specific alpha-1 adrenergic receptor agonist

Question 38

what is the main difference between phenylephrine and pseudoephedrine?

Answer 38

both cause vasoconstriction in the nasal mucosa, but phenylephrine does not lead to smooth muscle relaxation in the bronchi or impact the heart

Question 39

which is technically the more effective decongestant, phenylephrine or pseudoephedrine?

Answer 39

pseudoephedrine

Question 40

is there an abuse liability with the use of phenylephrine?

Answer 40

no, because it cannot be transformed into methamphetamine

Question 41

what is oxymetazoline?

Answer 41

an alpha-2 adrenergic agonist

Question 42

how is oxymetazoline administered?

Answer 42

as a spray (delivered directly to the nasal mucosa means more rapid onset of action and avoids side effects of a systemically administered alpha-2 adrenergic agonist)

Question 43

what is a risk of prolonged use of oxymetazoline?

Answer 43

rhinitis medicamentosa (aka rebound congestion)

Question 44

what are expectorants?

Answer 44

oral drugs that enhance the clearance of mucus

Question 45

what is the only available expectorant today?

Answer 45

guaifenesin (mucinex)

Question 46

increases the output of bronchial secretions by decreasing the adhesiveness and surface tension

Answer 46

guifenesin

Question 47

what is guaifenesin derived from?

Answer 47

bark from the guiac tree

Question 48

what is the mechanism of action of guaifenesin?

Answer 48

unknown