Respiratory: Cough

Question 1

What is a cough?

Answer 1

1. Reflex response to airway irritation

2. Protective reflex that removes foreign material and secretions from bronchi and bronchioles

Question 2

What are the two types of coughs?

Answer 2

1. Dry cough: felt as a tickle that sets off the coughing

2. Productive cough: chesty cough that produces phlegm

Question 3

How does the coughing mechanism actually occur?

Answer 3

1. Stimulation of airway cough receptors by irritants or conditions that cause airway distortion
2. Afferent nerves (low threshold, mechanosensors, chemosensors) provide modifying input to brainstem neural elements
3. This controls respiration and it helps generate cough respiratory pattern

Question 4

What is a acute cough, the duration and the causes?

Answer 4

1. Upper respiratory tract infection that triggers an airway cough receptor lead to airway distortion
2. Duration: Less than 3 weeks
3. Causes:
   - Acute bronchitis
   - Pneumona
   - Acute exacerbations of asthma
   - COPD
   - Bronchiectasis
   - Foreign body aspiration

Question 5

What is a chronic cough, the duration and the causes?

Answer 5

1. Smoking related causes, drugs, airway inflammation, gastro-oesophageal reflux.
   Airway cough receptors and airway distortion
2. Duration: more than 8 weeks
3. Causes:
   - Smoking related causes: COPD

• Angiotensin converting enzyme inhibitors
• Asthma
• Upper airway cough syndrome: caused by
  chronic rhinitis, chronic sinusitis
• Gastro-oesophageal reflux

Question 6

Whats the simple home remedy for a cough?

Answer 6

Honey and lemon

Question 7

How do you treat a child under 6 with a cough?

Answer 7

1. Do not give them over the counter cough and cold treatments that contain cough medicines
2. Warm drink of lemon and honey
3. Glycerol and honey

Question 8

What are the four cough medicines that are used?

Answer 8

1. Antitussives
2. Sedative antihistamines
3. Mucolytics
4. Expectorants

Question 9

What are Antitussives and give some examples?

Answer 9

1. Inhibit cough reflex by reducing sensory reception activation
2. Depresses cough centre in brain stem
3. Examples:
   Methanol vapour and topical anaesthetic

Question 10

How does a peripheral acting antitussive work, its use and administration?

Answer 10

1. Reduces sensitivity of peripheral sensory cough receptors
2. Works on pharynx and larynx to stop irritation
3. Use: treatment of productive and non productive cough
4. Administration: topical: spray, lozenge, vapour

Question 11

How does methanol work to suppress the cough, the form and how long it lasts?

Answer 11

1. Inhalation
2. Menthol crystals or proprietary capsules
3. Cough suppression is acute and short lasting

Question 12

Give examples of Antitussives that reduce the sensitivity of the cough centre and how do they act?

Answer 12

Examples:
1. Dextromethorphan

2. Codeine
3. Pholcodine

Central acting of opioid receptor to depress cough centre in brain stem.

Only used for treatment of dry cough only via oral administration

Question 13

What’s the warning for antitussives that reduce the sensitivity of the cough centre?

Answer 13

Do not combine with mucolytics or expectorants

Question 14

What is Dextromethorphan?

Answer 14

1. non sedating opiate (synthetic opioid, codeine analogue)
2. OTC drug
3. Available as liquid and lozenges
4. Preparations suitable for children under 12 years old

Question 15

What is codeine, it’s unwanted effects, and its do not use in?

Answer 15

1. Not greater efficacy than dextromethorphan, has great adverse side effects
2. Class B CD
   15mg codeine phosphate linctus is the maximum concentration for OTC
3. Do not use in:
   - Patients with asthma (respiratory depression)
   - Patient under 18 years

Question 16

What is pholcodine?

Answer 16

1. Opioid receptor agonist
2. Class B controlled drug
3. As efective as codeine with attenuated side effects

Question 17

What are sedative antihistamines, what is its suitability and what does it interact with?

Answer 17

1. First generation antihistamines
2. Chloraphenamine
3. Suppress cough but may cause drowsiness
4. Suitable for nocturnal cough
5. Interacts with the drugs: antidepressants and drugs that cause drowsiness

Question 18

What are Mucolytics?

Answer 18

1. Drugs that cleave disulphide bonds cross linking mucus glycoprotein
2. Reduces viscosity of bronchial secretion (liquefy mucus and phlegm)

Question 19

Give examples of mucolytics?

Answer 19

1. Carbocisteine
2. Mecysteine
3. N-acetylcysteiene

Question 20

What are Expectorants?

Answer 20

1. Drugs that promote expulsion of mucus by reducing adhesiveness and surface tension
2. Encourage productive cough and bronchial secretion (bring up phlegm to make coughing easier)

Question 21

Give examples of Expectorants?

Answer 21

1. White squill
2. Ipecacuanha
3. GUAIFENSIN
4. Cresoates
5. Volatile oils

Question 22

What is Guaifenesin?

Answer 22

1. Guaifenesin is an expectorant which increases the output of phlegm (sputum) and bronchial secretions by reducing adhesiveness and surface tension.
2. The increased flow of less viscous secretions promotes ciliary action and changes a dry, unproductive cough to one that is more productive and less frequent.
3. By reducing the viscosity and adhesiveness of secretions, guaifenesin increases the efficacy of the mucociliary mechanism in removing accumulated secretions from the upper and lower airway