Respiratory Flashcards
Salbutamol: Indications
Asthma: SABA or LABA w. corticosteroid
COPD
Hyperkalaemia
Salbutamol: Mechanism of Action
GPCR mediated smooth muscle relaxation
Also stimulate Na+/K+ ATPase so shift K+ to intracellular compartment
Salbutamol: Adverse Effects
Relate to stimulation of B receptors in other systems: palpitations, tachycardia, anxiety, tremor
Can also cause hyperglycaemia and muscle cramps
Salbutamol: Warnings and Interactions
LABA alone is associated with an increase in asthma deaths
Take care in patients with CVD, due to the risk of tachycardia and arrhythmia
Can reduce the effectiveness of B agonists
Salbutamol: Prescription
SABA inhaled as needed Given by nebuliser acutely LABA used twice daily in combination inhaler e.g. symbicort Monitoring by serial PEFR measurement Check inhaler technique
Anti-Muscarinics (ipatropium, tiotropium): Indications
COPD (short acting e.g. tipatropium as needed, long acting e.g. ipatropium for prevention)
Asthma
Anti-Muscarinics (ipatropium, tiotropium): Mechansim of Action
Competitively inhibit ACh so reduce parasympathetic tone. This causes smooth muscle relaxation and a reduction in glandular secretions
Anti-Muscarinics (ipatropium, tiotropium): Adverse Effects
Very few as there is little systemic absorption
Can cause dry mouth
Anti-Muscarinics (ipatropium, tiotropium): Warnings and Interactions
Can cause a risk in intraocular pressure so could affect closed angle glaucoma
Caution in patients at risk of arrhythmia
In practice, they can usually be inhaled by these patients with few issues
Interactions not generally an issue as they are inhaled
Anti-Muscarinics (ipatropium, tiotropium): Prescription
Inhaler or nebuliser (for acute treatment)
LAMA once daily
Advise about dry mouth: chew gum, suck sweets
Check inhaler technique
Monitor symptoms and PEFR measurements in asthmatics
Corticosteroids, inhaled (beclometasone, budesonide): Indications
Asthma (Step 2 treatment)
COPD
Corticosteroids, inhaled (beclometasone, budesonide): Mechanism of Action
They are steroids, so the pass through the cell membrane and act on nuclear receptors. They alter the transcription of a variety of genes related to inflammation. Interleukins, cytokines and chemokine are down regulates, and anti-inflammatory proteins are up regulates. This reduces mucosal inflammation and mucus secretion and widens the airway.
Corticosteroids, inhaled (beclometasone, budesonide): Adverse Effects
Local effects: Immunosuppression, so candida infection can occur. Hoarse voice,
Systemic (rare, only at high doses because of low systemic absorption): adrenal suppression, growth retardation, osteoporosis.
Corticosteroids, inhaled (beclometasone, budesonide): Warnings and Interactoins
Caution in children (growth suppression) and COPD patients with a history of pneumonia
They have no clinically significant interactions
Corticosteroids, inhaled (beclometasone, budesonide): Prescription
Usually twice daily by inhaler
Inhaler technique should be taught and assessed.
Monitored by symptoms, and PEFR in asthma
Oxygen: Indications
Increase tissue oxygen delivery in hyperaemia
Speed up reabsorption of gas in pneumothorax
Reduce half life of carboxyhemoglobin in CO poisoning
Oxygen: Mechanism of Action
Increased PaO2
Decreased alveolar N2 concentration, to pleural gas is reabsorbed and breathed out quicker
Competes with CO to bind to Hb
Oxygen: Adverse Effects
Discomfort from mask
Dry throat
Oxygen: Warnings and Interactions
Patients with chronic T2 respiratory failure and CO2 retention (e.g. COPD) may experience respiratory depression if the O2 saturation gets too high
It should not be exposed to heat of flame as it accelerates combustion
Oxygen: Prescription
Monitor by spO2 and ABG measurements
Target 94 to 98% in healthy people
Target 88 to 92% in COPD
