Respiratory Drugs Flashcards
What is the mechanism of beta2 agonists?
Bronchodilation of the airways - allow more air to ventilate the alveoli
Also increase mucus clearance via cilia action
Prevent bronchoconstriction prior to exercise
What are the contraindications of beta-2 agonists?
Increase heart rate as they stimulate the SAN, this is particularly a problem in those who suffer from cardiac issues, also decrease refractory period at AVN.
Adrenergic -FOFR
Increased glycogenolysis and renin
Muscle cramps (LABA)
What is the mechanism of action of glucocorticoids in asthma?
Reduces chronic inflammation, improving respiration. It is particularly effective at targeting eosinophils
Why might a spacer be given?
It aids correct administration of medication, through proper inhalation. Particularly helpful in children and the elderly.
Why is there a difference between asthma and COPD nebulisation?
Asthma - O2
COPD- air, since hypercapnia now drives respiration as the choroid plexus detects chronic CO2 and the peripheral chemoreceptors take over. Therefore since the respiratory drive is now due to pO2, this would be lost if nebulized with o2.
What medication is recommended to be taken if glucocorticoids aren’t sufficient enough to manage asthma?
Long acting beta agonists
Why do LABAs always need to be prescribed with glucocorticoids?
Without them, they increase the likelihood of death
What is the main concern when prescribing glucocorticoids to COPD patients?
Increased risk of infection, since glucocorticoids act as immunosuppressants.
Before stepping up or down asthma medication, what key considerations should be made?
- adherence
- inhaler technique
- eliminate trigger factors
What is the next step once a regular preventer become insufficient?
Inhaled corticosteroids - reduce mucosal inflammation, widen airway, reduce mucus.
Includes beclometasone, budesonide and fluticasone.
What are the ARDs implicated from inhaled corticosteroid use?
Pneumonia risk
Local immunosuppressive action- oral candidiasis and hoarse voice
What types of B2 agonists are there?
SABA - reversal of bronchoconstriction
LABA- add on therapy
Name a short and fast acting b2 agonist
Salbutamol
Terbutaline
Name a long and fast acting b2 agonist
Formoterol
Name a long and slow acting b2 agonist
Salmeterol
Why might formoterol be prescribed over salmeterol?
More potent and efficacious
What therapy might be added to an asthmatics medication?
Leukotriene receptor antagonists - montelukast
What it the mechanism of action of LTRA?
LTRA block CysLT1
Prevents LTC4 released by mast cells/eosinophils - which causes bronchoconstriction, mucus and oedema.
What is the ADRs of LTRA?
Headache
GI disturbance
Dry mouth
Hyperactivity
What additional controller therapies might be prescribed?
Ipratropium-Long acting muscarinic antagonist - severe asthma and COPD, selective for M3. Anticholinergic effects via inhibition.
Theophylline - a methylxanthine p.o adenosine receptor antagonist.
What are the ADRs of tiotropium (LAMA)?
Dry mouth
Urinary retention
Dry eyes
What are the potential issues with theophylline?
Narrow therapeutic index - life-threatening complications including arrhythmia.
Interaction with CYP450 inhibitors - increase concentration
What specialist maintenance therapy might be prescribed for asthmatics?
Oral steroids- prednisolone
For severe uncontrolled asthma, carry steroid card.
Post acute exacerbation - at least 5 days
Post acute COPD- 5-7 days
What are the treatment plans for those with acute severe or life threatening asthma?
Oxygen
High dose nebulised B2 agonist
Oral steroids for 7-14 days in addition to ICS
If poor response give nebulised ipratropium bromide (SAMA).
Consider IV aminophylline if life threatening with no success.
