Respiratory Pharmacology Flashcards
Examples of inhaled corticosteroids
Beclometasone
Budesonide
Fluticasone
What is the mechanism of action of inhaled corticosteroids for asthma management?
- pass through plasma membrane > activate cytoplasmic receptors > receptors pass into nucleus to modify transcription
- reduce mucosal inflammation, widens airways + reduces mucous
- reduces symptoms, exacerbation + prevents death
What are adverse drug reactions of inhaled corticosteroids?
Local immunosuppressive action - candidiasis + hoarse voice
What are contraindications of inhaled corticosteroids?
Pneumonia risk in possible COPD at high dose
Step wise management of asthma in adults
- low dose ICS
- inhaled LABA added
- increase ICS dose or add leukotriene receptor antagonist
- refer for patient specialist care
. - and SABA as required
Describe the basic mechanism of how steroid work
Outline the pharmacokinetics of inhaled corticosteroids
- poor oral bioavailability
FINISH
Examples of SABA
Salbutamol
Terbutaline
Examples of LABA
Salmeterol
Formoterol
Compare when SABA and LABA are used?
- SABA: symptoms relief as required
- LABA: add on therapy to ICS in asthma treatment
What is the mechanism of action of SABA + LABA
- B2 agonists
- Act on airway smooth muscle > increase cAMP > increase protein kinase A > bronchodilation
- increase mucous clearance by action of cilia
What are adverse drug reactions of B2 agonists
- tachycardia
- palpitations
- anxiety
- tremors
- increased glycogenolysis + renin
- superventicular tachycardia (rare)
Why should LABA only be prescribed alongside ICS?
Alone can mask airway inflammation + (near) fatal attacks
What are important drug drug reactions of B2 agonists
B blockers
Example of leukotriene receptor antagonist
Montelukast
What is the mechanism of action of montelukast?
leukotriene receptor antagonists
blocks CysLT1 at CYSLTR1
- decreases action of leukotriene from mast cells/eosinophils
- decreases bronchoconstriction, mucous + oedema
What class of drug is montelukast?
Leukotriene receptor antagonist
What are adverse drug reactions of montelukast?
Headache
GI disturbance
Dry mouth
Examples of long acting Muscarinic antagonist
Tiotropium
What class of drug is tiotropium?
Long acting Muscarinic antagonist
What are the uses of tiotropium?
Severe asthma
COPD
What is the mechanism of action for tiotropium?
- LAMA with selectivity for M3 recpetors
- Blocks vagally mediated contraction of airway smooth muscle
What is the adverse drug reactions of tiotropium?
Anticholinergic effects:
- Dry mouth
- Urinary retention + constipation
- Dry eyes
What class of drug is theophylline?
Adenosine receptor antagonist
Phosphodiesterase inhibitor
What are the uses of theophylline?
Chronic poorly controlled asthma
What are important drug drug reactions of theophylline?
CYP450 inhibitors - increase concentrations
When should an asthmatic self managment plan be reviewed?
Following treatment of exacerbation
On discharge from hospital following acute attack
When should life threatening asthma be suspected?
- Unable to complete sentences
- peak flow 33-50% of their best
- resp rate >25
- > 110bpm
- cyanotic
- <92% O2 sats
Treatment of acute severe + life threatening asthma
- 2.5-5mg salbutamol
- 50mg oral prednisolone for minimum 5 days + continue ICS
What is the class of drug of ipratropium?
Short acting muscarinic antagonist
Examples of steroids given in acute severe asthma
Prednisolone
Hydrocortisone
Treatment of acute exacerbations of COPD
- Nebulised salbutamol and or ipratropium
- oral steroids
- antibitoics (narrow spectrum if less severe, broad in greater severity)
What are the inhaler options?
How does the technique differ?
- Pressurised metered dose inhalers: slow breath in + hold
- dry powder inhalers: own inspiratory flow (faster + deep inhalation)
Why do ICS have relatively few systemic side effects?
- low oral bioavailability
- when absorbed P.O. > transported from stomach to liver
- almost compete first pass metabolism
5 tasks of managment of COPD
- Confirm diagnosis
- smoking cessation
- record MRC dyspnea score
- annual flu + pneumococcal vaccinations
- medication e.g. inhalers
Drug treatment of TB + course length
- rifampicin: 6 months
- isoniazid: 6 months
- ethambutol: 2 months
- pyrazinamide: 2 months
What are adverse drug reactions of TB meds?
- hepatitis: rifampicin, isoniazid, pyrazinamide
- visual disturbances: ethambutol
- peripheral nerve damage: isoniazid
- orange secretions: rifampicin
What addition management needs to be given for TB alongside the drugs and why?
Vitamin B6
Limit peripheral nerve damage from isoniazid
Difference in NICE + BTS stepwise asthma management
- low dose ICS first for both
- NICE: add LTRA
- BTS: add LABA
Describe why inhale drug particles that are too small AND too big are ineffective in asthma management
- too small: inhaled in alveoli + exhaled without deposition in lung
- too big: deposition in mouth and oropharynx
what is the mechanism of action of beta agonists?
- bind to B2 adrenergic recpeotr on smooth muscles lining the airway
- activates adenylate cyclase
- this converted ATP > cAMP
- cAMP activates PKA
- causes smooth muscle relaxation > bronchodilation
Example of SAMA + LAMA
SAMA: ipratropium
LAMA: tiotropium
