Cough & Cold

Question 1

List the classes of drugs used for rhinorrhoea (runny nose/sneezing) and nasal congestion (blocked nose)

Answer 1

(1) Mucoregulator - intranasal ipratropium
(2) Mast cell stabiliser - intranasal/inhaled cromoglicic acid
(3) H1 antihistamines
(4) Decongestants:
(A) intranasal corticosteroid
(B) sympathomimetic decongestants

Question 2

List the classes of drugs used for sore throat, headache and fever associated with common cold.

Answer 2

(1) Analgesics e.g., NSAIDs or paracetamol
(2) Antipyretics e.g., NSAIDs or paracetamol

Question 3

List the classes of drugs used for cough.

Answer 3

(1) For “dry”/non-productive cough: Antitussives (cough suppressants)
(2) For “wet”/productive cough:
(A) Expectorants
(B) Mucoactive agents:
(i) Mucolytics
(ii) Mucokinetics

Question 4

What is post-nasal drip?

Answer 4

Post-nasal drip is when mucus drips down from the back of the inflamed nasal cavity into the nasopharynx and hence the throat.
Post-nasal drip can cause cough. Cough caused by post-nasal drip can be alleviated by the classes of drugs used to treat rhinorrhoea (mucoregulators, mast cell stabilisers, antihistamines, and decongestants).

Question 5

For the treatment of rhinorrhoea associated with common cold, which classes of drugs have the greatest evidence of clinical efficacy?

Answer 5

Evidence-based medicine suggests that (1) analgesics (2) mucoregulators (e.g., intranasal ipratropium), and (3) mast cell stabilisers (e.g., cromoglicic acid) may be effective.

Likewise, there is evidence that antihistamines and decongestants combined may be effective, but the evidence for the efficacy of antihistamines or decongestants alone is minimal or uncertain.

Question 6

Name an example of a mucoregulator used to treat symptoms of common cold. Briefly, explain its route of administration and mechanisms of action.

Answer 6

Ipratropium bromide
- Delivered intranasally
- Short-acting muscarinic receptor antagonist (SAMA)
- Blocks inflammation‐induced parasympathetic - cholinergic receptor (M3) activation of submucosal glands/goblet cells
- Importantly, does not dry basal secretion and does not increase the normal viscosity of mucus.

Question 7

List common adverse effects of ipratropium when administered intranasally

Answer 7

Few side effects as little enters systemic circulation via - - intranasal route
- Unpleasant taste
- Dry mouth
- Urinary retention (elderly particularly susceptible)

Question 8

Name a mast cell stabiliser that can be used to control symptoms of common cold. Briefly explain the route of administration and the mechanisms of action.

Answer 8

Cromoglicic acid
- Intranasal or inhaled
- Controls chloride (Cl-) channels to inhibit cellular activation
- ↓mast cell degranulation induced by IgE-mediated FcεRI crosslinking
- ↓ secretion of inflammatory mediators from eosinophils, neutrophils and macrophages
- ↑ secretion of annexin A1
- AnnexinA1 inhibits prostaglandin and leukotriene production

Question 9

List common side effects of cromoglicic acid

Answer 9

Throat and nasal irritation, mouth dryness, cough
Unpleasant/Bitter taste

Question 10

List FIVE examples of sympathomimetic decongestants.

Answer 10

1. Phenylephrine (direct alpha-1 agonist)
2. Oxymetazoline (nonselective direct alpha agonist)
3. Naphazoline (nonselective direct alpha agonist)
4. Pseudoephedrine (indirect sympathomimetic)
5. Ephedrine (indirect sympathomimetic)

Question 11

List typical routes of administration of common sympathomimetic decongestants

Answer 11

Direct alpha adrenoceptor agonists
- Alpha-1 selective: Phenylephrine (oral or intranasal)
- Non-selective: Oxymetazoline (intranasal) / naphazoline (intranasal)
Indirect increase in release of adrenaline/noradrenaline
- Pseudoephedrine (oral) / Ephedrine (intranasal)

Question 12

Name TWO examples of corticosteroids administered intranasally as decongestants

Answer 12

1. Fluticasone
2. Mometasone

Question 13

Intranasal administration of corticosteroids reduces the risk of systemic adverse effects. What is the MOST LIKELY adverse effect of intranasal corticosteroids?

Answer 13

Local mucosal dryness and irritation

Question 14

Intranasal administration of corticosteroids reduces the risk of systemic adverse effects.
What is an adverse effect specific to intranasal fluticasone that can affect compliance in some patients?

Answer 14

Some people report that intranasal fluticasone has a “rose water” odour that they cannot tolerate

Question 15

Intranasal administration of corticosteroids reduces the risk of systemic adverse effects.
What is an adverse effect specific to intranasal fluticasone that can affect compliance in some patients?

Answer 15

Some people report that intranasal fluticasone has a “rose water” odour that they cannot tolerate

Question 16

List common adverse effects of sympathomimetic decongestants.

Answer 16

Rebound congestion
- Occurs with prolonged (> few days) topical intranasal use
CNS stimulation
- More likely with oral decongestants (e.g., pseudoephedrine or phenylephrine)
- Restlessness, tremors, irritability, anxiety and insomnia
Cardiovascular
- More likely with oral decongestants (e.g., pseudoephedrine or phenylephrine)
- Hypertension due to vasoconstriction
- Tachycardia (indirect sympathomimetics e.g., pseudoephedrine)
Dry mouth
- Alpha-2 agonist effect on salivary gland (e.g., oxymetazoline or pseudoephedrine but not phenylephrine)

Question 17

List THREE antitussive drugs

Answer 17

Opioid antitussives
- Codeine
Nonopioid antitussives
- Dextromethorphan
- Diphenhydramine

Question 18

List advantages and disadvantages of codeine as an antitussive

Answer 18

Advantages:
- Most effective antitussive
Disadvantages (greater for CYP2D6 ultra-rapid metabolisers who convert more codeine to morphine faster):
- Potential for abuse
- Sedation
- Respiratory depression on overdose

Question 19

List advantages and disadvantages of dextromethorphan as an antitussive

Answer 19

Advantages:
- Less risk of addiction
​- Most effective non-opioid antitussive
Disadvantages:
- Drowsiness, dizziness (although less than codeine)
- Gastrointestinal adverse effects
- Potential for abuse at high doses

Question 20

List advantages and disadvantages of diphenhydramine as an antitussive

Answer 20

Advantages
- No risk of addiction
Disadvantages
- Sedation
- Anticholinergic adverse effects

Question 21

Below what age is codeine not recommended as an antitussive?

Answer 21

Codeine is not recommended as antitussive < 18 years old.

Question 22

Below what age is dextromethorphan not recommended as an antitussive?

Answer 22

Not recommended < 4 years old

Question 23

Below what age is guaifenesin not recommended?

Answer 23

Caution < 6 years old
Not indicated < 2 years old

Question 24

Below what age are sympathomimetic decongestants contraindicated?

Answer 24

Below 12 years old

Question 25

What is the MOST IMPORTANT advice for a patient prescribed guaifenesin?

Answer 25

Take adequate fluid to make secretions less viscous and
protect renal function (nephrolithiasis reported on overdose)

Question 26

To what class of drugs does guaifenesin belong?

Answer 26

Expectorants

Question 27

Name TWO examples of mucolytics

Answer 27

Acetylcysteine, carbocisteine

Question 28

Name TWO examples of mucokinetics

Answer 28

Bromhexine and its active metabolite ambroxol