Respiratory Flashcards
What class of drugs does carbocysteine belong to?
Mucolytics
What is the mechanisms by which carbocysteine works?
- Alters the metabolism of mucus secreting cells
- Reduces mucus viscosity, reduces bronchial inflammation and reduces bronchospasm
What are the indications for carbocysteine/mucolytics?
COPD
Bronchiectasis
Chronic bronchitis
What are the CI for using mucolytics
Peptic ulcers - removes protective muscus barrier
1st trimester of pregnancy (avoid)
What are the SEs of using mucolytics?
GI bleeding
How are mucolytics excreted?
Renally
Name 2 short acting B2 agonists and 2 long acting B2 agonists
SA: salbutamol, Terbutaline
LA: Salmeterol, Formeterol
What is the mechanism for B2 agonists?
B2 receptors found in smooth muscle of bronchi, GI tract, uterus and blood vessels
Activation causes smooth muscle relaxation - dilates airways and inmproves airflow
Also acts on NaK-ATPase pumps on cell surface membranes. Shifts K intracellularly. Treatment for hyperK+
What are the indications for B2 agonists?
Asthma: SA - relieve SOB. LA: 3rd stage of treatment for chronic asthma. MUST be used in combo with a corticosteroid
COPD. SA: relieve SOB. LA: 2nd line treatment for COPD
HyperK+: nebulised salbutamol (in combo with insulin, glucose and calcium gluconate)
What are the CIs for Beta2 agonists?
CV disease - can precipitate arrhythmias/angina
LA - must be used in combo with corticosteroid. Without = associated with asthma related deaths
What are the SE for Beta2 agonists?
- Palpitations
- Tachycardia
- Tremor
- Anxiety
- Hyperglycaemia
- Muscle cramps
What are the interactions B2 agonists?
- reduce effectiveness of Beta blockers
- Hypo k+ in combo with K+ reducing drugs (e.g. diuretics e.g. loop/thiazie, corticosteroids and theophylline)
Name two long acting anticholinergics and one short acting
LA: tritropium, glycopyrronium
SA: Ipratropium
What is the mechanism by which anticholinergics exert their action?
Competitive inhibitor of acetylcholine - blocks cholinergic receptors
Reduced parasympathetic tone which reduces smooth muscle contraction, reduces secretion and increases HR/conduction
Also reduces pupillary constrictor and muscles, causing dilatation and loss of accomodation
What are the indications for anticholinergics?
- COPD: SA: reduce SOB. LA; prevent exacerbation and SOB
- Asthma: adjuvant therapy for relief of SOB during acute exacerbations (added to long term B2 agonist. LAMAs to high dose inhaled corticosteroids and long term B2 agonists for chronic asthma
What are the CI for anticholinergics?
Patients with arrythmias
Patients with angle closure glaucoma - could increase intra-occular pressure
What are the SEs of anticholinergics?
Not systemically absorbed so not many SEs!
Dry mouth
What are the interactions of anti-cholinergics?
Not generally problem due to non-systemic absorption
Name 3 inhaled corticosteroids
Beclometasone
Budesonide
Fluticasone
Name 3 oral corticosteroids
Prednisone
Hydrocortisone
Dexamethasone
How do corticosteroids exert their action?
Bind to glucocorticoid receptors > translocate into nucleus - bind to glucocorticoid > response elements > gene expression regulation
Down regulate inflammatory gene s and up regulate anti-inflammatory genes
- reduce monocytes and eosinophils
- Reduces infiltration of leukocytes
- reduces production of leukotrienes and prostaglandins
- reduces leakiness and vasodilation of capillaries
- Increased gluconeogeneis - increases catabolism of muscle and fat
- Increases Na and H2O retention and K+ excretion
What are the indications for corticosteroids?
Allergic or inflammatory disorders e.g. anaphylaxis, asthma
Suppression of auto immune diseases e.g. SLE, RA, IBD
Tx of some cancers - reduces tumour associated swelling
Hypo-pituitaraism or adrenal insufficiency
What are the CIs for corticosteroids?
Children (growth suppression)
Active infection (e.g. pneumonia)
What are the SEs of corticosteroids?
- Immunosuppression
- Metabolic - diabetes, osteoperosis
- Psych - insomnia, anxiety, psychosis, suicidal ideas
- Increased catabolism - muscle weakness, skin thinning, easy bruising, gastritis
- Hypertension hypoklaemia, oedema
- Suppression of pituritary ACTH secretion - adrenal atrophy.
If suddenly withdrawn, ADDISONIAN CRISIS!
What are the interactions of corticosteroids?
HypoK+ if combined with diuretics, beta agonists and theophylinnes
NSAIDs - increased risk of peptic ulcers/GI bleeding
Efficacy reduced with cytochrome P450 inducers
Reduce immune response to vaccines
What time of the day should you take corticosteroids?
One in the day to mimic normal circadian rhythm
What are the mechanisms for theophyllines?
Blocks type III/IV phosphodiesterase - reduces breakdown of smooth muscle cAMP and increases bronchodlation
Blocks adenosine AIIB receptors - prevents adenosine mediated bronchoconstriction. Also increases HR
Activates histone deacetylase - prevents transcription of pro-inflammatory genes
What are the indications for theophyllines?
- COPD - but not acute exaccerbations
- Empysema
- Acute/chronic asthma
What are the CIs for theophyllines?
Low therapeutic index
- Arrthymias
- HTN
- Hyperthyroidism
- Peptic ulcer
- Epilepsy
- Elderly
- fever
- Hypo-K+
What are the SEs of theophyllines?
Palpitations Tachycardia Arrythmias GI distrubance CNS stimulation Convulsion Headache
What are the indications for Oxygen?
- increase tissue oxygen delivery in state of hypoxaemia
- Accelerate reabsorption of pleural gas (nitrogen) in pneumothorax
- Reduces half-life of carboxy-haemoglobin in carbon monoxide poisoning
What are the CI of oxygen?
Type II respiratory failure (e.g. COPD) - increase oxygen reduces respiratory drive, increasing PaCO2 > resp acidosis > loss of conciousnessness and worsened hypoxaemia
- near a fire source!! (ie. dont smoke)
