W13 42 drug treatment of respiratory disease/obstructive airway disease

Question 1

When is high flow vs controlled flow oxygen delivered?

Answer 1

High flow in respiratory emergencies (around 15L/min)
Controlled oxygen in chronic hypoxic conditions (around 2-4L/min)

Question 2

What are the different delivery methods on oxygen?

Answer 2

High flow - non-rebreathe mask
Venturi devices - controlled % of O2 delivery
Nasal speculae - 2-4L/min

Question 3

Allergic rhinitis is an upper airway disease. What drugs are used for this?

Answer 3

Antihistamines eg chlorphenamine, loratidine, cetirizine. Have muscarinic effects like effecting CNS.
Decongestants - eg ephedrine, pseudoephedrine. Interact with MAOIs and TCAs.

Question 4

What ADRs come from antihistamines and decongestants?

Answer 4

Antihistamines - drowsiness, xerostomia, hypersensitivity reactions
Decongestants - anxiety, xerostomia

Question 5

What drugs can be used for asthma?

Answer 5

Inhaled bronchodilators
Oral bronchodilators
Inhaled corticosteroids
Inhaled long-acting beta2 agonists
Leukotriene agonists
Mast cell stabilisers

Question 6

Examples of inhaled bronchodilators

Answer 6

Salbutamol, terbutaline - short-acting beta2 agonists
Blue inhaler
Widely used, minimal ADRs (tremor)

Question 7

Examples of oral bronchodilators

Answer 7

Salbutamol tablets - not widely used
Theophylline - narrow therapeutic index, lots of drug interactions

Question 8

Examples of inhaled corticosteroids and what inhaler are they in?

Answer 8

Beclometasone, fluticasone, budesonide
Widely used, few systemic ADRs
Red/brown inhaler
(Prolonged use can cause adrenal suppression but this is more oral corticosteroids)

Question 9

Examples of inhaled long-acting beta2 agonists

Answer 9

Salmeterol, formoterol
(Third line, often combined with corticosteroids)
Few ADRs and interactions
Red/brown inhaler

Question 10

Examples of leukotriene antagonists and what do they interact with?

Answer 10

Montelukast
Oral drugs used at 3rd or 4th line
Interacts with carbamezepine (decreased exposure)

Question 11

When are mast cell stabilisers used?

Answer 11

Rarely, but for exercise asthma
Causes coughing and throat irritation

Question 12

What drugs are used for LRTI or pneumonias, and what’s the dental relevance?

Answer 12

Erythromycin/clarithromycin - can cause tooth/tongue discolouration, multiple interactions

Question 13

What drugs can be used in pulmonary TB?

Answer 13

Rifampicin, isoniazid

Question 14

How does particle size affect delivery?

Answer 14

Particle size is proportional to deposition
Generally want drugs down into the airways to decrease inflammation and open the airway up. 2-5microns is ideal.
10microns = mouth to large airway, 5microns is small airways, 2microns is alveoli, less than 1 micron might be exhaled again

Question 15

What are the different delivery methods of respiratory drugs?

Answer 15

MDIs - metered dose inhalers
Spacer devices
Nebuliser

Question 16

Describe MDIs - metered dose inhalers

Answer 16

Required coordination
Each actuation contains a measured dose
Convenient to carry
Multiple puffs via spacer in an emergency

Question 17

What do b2 agonists do?

Answer 17

B2 agonists will act on b2 receptors on airway smooth muscle, causing a cyclic AMP change and dilatation of the airways via relaxation.

Question 18

What are spacer devices and what are their pros and cons?

Answer 18

Valves holding chambers. Reduce the need for coordination of MDI inhalations. Reduces risk of adverse effects with inhaled corticosteroids (like oral thrush). Also reduced amount of medication that is absorbed into the system. Less convenient to carry. Should be advised to use.

Question 19

What does a nebuliser do?

Answer 19

Compressed air or ultrasonic energy. Produce aerosolised particles 1-5microns in size.

Question 20

What are some adverse drug effects (dental related) of respiratory medications?

Answer 20

Dental caries from beta-2 agonists
Oral candidiasis from inhale corticosteroids

Question 21

How do beta-2 agonists cause dental caries?

Answer 21

Prolonged use can decrease saliva production/secretion
Also reduced salivary and plaque pH

Question 22

How do you reduce the risk of dental decay from beta-2 agonists?

Answer 22

Rinse mouth immediately after inhaler
Increase saliva production using sugar-free gum

Question 23

How do you reduce risk of oral candidiasis from inhaled corticosteroids?

Answer 23

Use a spacer device
Rinse mouth with water after inhalation

Question 24

How do you treat oral candidiasis without discontinuing asthma therapy?

Answer 24

Antifungal oral suspension

Question 25

How do you deal with an acute asthma attack?

Answer 25

ABCDE
Most response to 2 puffs of a short-acting beta2 agonist inhaler (eg salbutamol 100micrograms/puff)
Further puffs if pt doesn’t respond rapidly. Call 999 if unsatisfactory/no response or if severe/life-threatening
Large-volume spacer device if pt can’t use inhaler (or plastic cup with a hole in bottom for inhaler mouthpiece)

Question 26

What does the BNF say about chronic asthma and dental treatment?

Answer 26

Patients with severe chronic asthma or whose asthma has deteriorated previously during a dental procedure may require an increase in their prophylactic medication before a dental procedure. This should be discussed with the patients medical practitioner and may include increasing the dose of inhaled or oral corticosteroid.

Question 27

Dental considerations of asthmatic patients

Answer 27

Understand level of asthma control - have they taken on day of appt, freq of reliever treatment, medications used
Ask pt to bring inhalers to each appt
Avoid known precipitating factors - eg aspirin, NSAIDs
Avoid erythromycin-like antibiotics in patients taking theophylline
Consider need for supplementary corticosteroids in patients with continuous/recurrent use
Pulmonary function tests prior to major interventions (eg conscious sedation or GA)

Question 28

How is COPD managed?

Answer 28

Bronchodilators and corticosteroids
Antibiotics if indicated
Vaccination (influenza annually, pneumococcal one-off dose)
Treat CCF
Oxygen therapy for respiratory failure
Smoking cessation

Question 29

Dental considerations of the COPD patient

Answer 29

Understand severity of illness and degree of respiratory compromise
Some patients require oxygen treatment during dental treatment which can be given via nasal speculae in specialised clinics
Any anything that will depress respiration further
Ensure patient is place in semi-supine or upright to prevent orthopnoea
Consider need for supplementary corticosteroids in those patients with continuous/recurrent use
Pulmonary function tests/anaesthetic assessment prior to major interventions (eg conscious sedation or amloGA)
Consider undiagnosed cardiovascular disease - for causes of chest pain
Concern over the use of supplemental oxygen

Question 30

What will depress respiration?

Answer 30

High dose opiates, benzodiazepines

Question 31

When should you give oxygen?

Answer 31

All sick patients should be given O2 until arrival of the ambulance.
In an emergency, hypoxia kills faster than carbon dioxide related respiratory depression

Question 32

How do you treat patients with chronic respiratory disease?

Answer 32

Usually with inhaled bronchodilators or corticosteroids
Generally continue peri-operative it
May need converting to nebulised route for delivery in immediate peri-op condition
High dose corticosteroids (esp in children) may require steroid cover to avoid Addisonian crisis

Question 33

Patients with underlying lung disease are more susceptible to respiratory complications following surgery. What should be considered during general anaesthetic?

Answer 33

Manipulation of already possibly irritable airway
Intubation can lead to bronchospasm
Reduced inspiratory effect post-op - difficulty with inhaled medicines
Opioid analgesic leads to reduced respiratory effort further