W13 42 drug treatment of respiratory disease/obstructive airway disease Flashcards
When is high flow vs controlled flow oxygen delivered?
High flow in respiratory emergencies (around 15L/min)
Controlled oxygen in chronic hypoxic conditions (around 2-4L/min)
What are the different delivery methods on oxygen?
High flow - non-rebreathe mask
Venturi devices - controlled % of O2 delivery
Nasal speculae - 2-4L/min
Allergic rhinitis is an upper airway disease. What drugs are used for this?
Antihistamines eg chlorphenamine, loratidine, cetirizine. Have muscarinic effects like effecting CNS.
Decongestants - eg ephedrine, pseudoephedrine. Interact with MAOIs and TCAs.
What ADRs come from antihistamines and decongestants?
Antihistamines - drowsiness, xerostomia, hypersensitivity reactions
Decongestants - anxiety, xerostomia
What drugs can be used for asthma?
Inhaled bronchodilators
Oral bronchodilators
Inhaled corticosteroids
Inhaled long-acting beta2 agonists
Leukotriene agonists
Mast cell stabilisers
Examples of inhaled bronchodilators
Salbutamol, terbutaline - short-acting beta2 agonists
Blue inhaler
Widely used, minimal ADRs (tremor)
Examples of oral bronchodilators
Salbutamol tablets - not widely used
Theophylline - narrow therapeutic index, lots of drug interactions
Examples of inhaled corticosteroids and what inhaler are they in?
Beclometasone, fluticasone, budesonide
Widely used, few systemic ADRs
Red/brown inhaler
(Prolonged use can cause adrenal suppression but this is more oral corticosteroids)
Examples of inhaled long-acting beta2 agonists
Salmeterol, formoterol
(Third line, often combined with corticosteroids)
Few ADRs and interactions
Red/brown inhaler
Examples of leukotriene antagonists and what do they interact with?
Montelukast
Oral drugs used at 3rd or 4th line
Interacts with carbamezepine (decreased exposure)
When are mast cell stabilisers used?
Rarely, but for exercise asthma
Causes coughing and throat irritation
What drugs are used for LRTI or pneumonias, and what’s the dental relevance?
Erythromycin/clarithromycin - can cause tooth/tongue discolouration, multiple interactions
What drugs can be used in pulmonary TB?
Rifampicin, isoniazid
How does particle size affect delivery?
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
What are the different delivery methods of respiratory drugs?
MDIs - metered dose inhalers
Spacer devices
Nebuliser
Describe MDIs - metered dose inhalers
Required coordination
Each actuation contains a measured dose
Convenient to carry
Multiple puffs via spacer in an emergency
What do b2 agonists do?
B2 agonists will act on b2 receptors on airway smooth muscle, causing a cyclic AMP change and dilatation of the airways via relaxation.
What are spacer devices and what are their pros and cons?
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.
What does a nebuliser do?
Compressed air or ultrasonic energy. Produce aerosolised particles 1-5microns in size.
What are some adverse drug effects (dental related) of respiratory medications?
Dental caries from beta-2 agonists
Oral candidiasis from inhale corticosteroids
How do beta-2 agonists cause dental caries?
Prolonged use can decrease saliva production/secretion
Also reduced salivary and plaque pH
How do you reduce the risk of dental decay from beta-2 agonists?
Rinse mouth immediately after inhaler
Increase saliva production using sugar-free gum
How do you reduce risk of oral candidiasis from inhaled corticosteroids?
Use a spacer device
Rinse mouth with water after inhalation
How do you treat oral candidiasis without discontinuing asthma therapy?
Antifungal oral suspension
How do you deal with an acute asthma attack?
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)
What does the BNF say about chronic asthma and dental treatment?
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.
Dental considerations of asthmatic patients
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)
How is COPD managed?
Bronchodilators and corticosteroids
Antibiotics if indicated
Vaccination (influenza annually, pneumococcal one-off dose)
Treat CCF
Oxygen therapy for respiratory failure
Smoking cessation
Dental considerations of the COPD patient
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
What will depress respiration?
High dose opiates, benzodiazepines
When should you give oxygen?
All sick patients should be given O2 until arrival of the ambulance.
In an emergency, hypoxia kills faster than carbon dioxide related respiratory depression
How do you treat patients with chronic respiratory disease?
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
Patients with underlying lung disease are more susceptible to respiratory complications following surgery. What should be considered during general anaesthetic?
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
