Respiratory Flashcards
A 12 year old female has been experiencing episode of shortness of breath and cough during school exercise activities and also at night time. She states she experiencing this almost five times a week. It is affecting her daily routine and is with mom to find out what she has? What is the likely diagnosis?
Asthma
DISCUSS SABA & LABA B2 agonist CLINICAL PHARMACOLOGY
SABA: Short acting B2 agonist used to relieve breathlessness. Have a rapid onset of action (15 minutes) and their effects last for up to 4 hours.
LABA: Long acting B2 agonist: Last for 12 hours
Drug examples:
SABA: Salbutamol and terbutaline
LABA: Salmeterol and formoterol
MOA:
- B2 receptors are found in the smooth muscle. Stimulation of the G protein
receptor activates the cascade leading to smooth muscle relaxation, stimulate
Na/K+ ATPase causing a shift of K from extra to intracellular compartment,
improving airflow of constricted or inflamed airway and reducing breathlessness.
Indications:
- Asthma
- COPD
- Hyperkalaemia
Adverse effects:
- Tachycardia
- Palpitations
- Anxiety
- Tremor
- Muscle cramps
- Activating beta receptors cause tremor, anxiety, tachycardia
Warnings (Cautions):
- Cardiovascular disease
- Beta blockers
- Angina
- Arrhythmias
- Hyperkalaemia
- LABA. Without a steroid, LABAs are associated with increased asthma deaths.
Contraindications:
- Hypersensitivity allergy to salbutamol
- Propranolol
- Cardiac glycosides.
Interactions:
- β-blockers may reduce the effectiveness of β2-agonists
- Concomitant use of high-dose nebulised β2-agonists with theophylline and corticosteroids can lead to hypokalaemia
Monitoring:
Consequently, if they find themselves needing to use the inhaler very frequently, then they should seek medical advice, or increase their other treatment. Peak flow rate can be monitored for symptom progression
What is asthma treatment plan.
- 1 st : SABA (Salbutamol)
- 2 nd ADD + ICS (Beclomethasone)
- 3 rd : ADD LTRA, (Leukotriene receptor antagonists, Montelukast )
- 4 th : LABA (Long-acting beta agonists- Salmeterol) + ICS (+/- LTRA)
- 5 th : (MART therapy (with Low dose ICS & LABA ) + LTRA)
- 6 th: Theophyline or muscurinic antagonist
DISCUSS INHALED CORTICOSTEROID CLINICAL PHARM
ICS: Inhaled corticosteroid.
Drug names: beclometasone, budesonide, fluticasone
MOA:
- Pro-inflammatory interleukins, cytokines and chemokines are downregulated, while antiinflammatory proteins are upregulated. In the airways, this reduces mucosal inflammation, widens the airways and reduces mucus secretion. This improves symptoms and reduces exacerbations in asthma and COPD.
Indications:
- Asthma
- COPD
Adverse effects:
- Oral Candidiasis
- Hoarse voice
- Increased risk of pneumonia
Warnings (Cautions):
- History of pneumonia (COPD patients)
- Children (growth suppression)
- High dose fluticasone caution in COPD patients
Contraindications
- No known contraindications of inhaled corticosteroids.
Monitoring:
Patients with asthma can monitor their disease severity through symptoms and serial peak expiratory flow rate measurements
Symptom severity and exacerbation rates are the main indicators of effect in COPD (3-6 months review)
DISCUSS LEUKOTRIENE RECEPTOR ANTAGONISTS (Montelukast) PHARM
LTRA
MOA:
- Activate G protein coupled leukotriene receptor cysLT1, activating cascade resulting in bronchoconstriction reducing
inflammation.
Indications:
- Asthma
Adverse effects:
- Headache
- Abdominal pain
- Hyperreactivity
- Reduced ability to concentrate
- Churg–Strauss syndrome, an eosinophilic autoimmune disorder
Warnings
- Needs to be prescribed with ICS
Contraindications
- None
Interactions:
- None
Monitoring:
- Efficacy should be monitored by symptom diary and serial measurement of peak expiratory flow rate.
DISCUSS THEOPHYLINE CLINICAL PHARM
Theophyline
MOA:
Theophylline relaxes the smooth muscle of the bronchial airways and pulmonary blood vessels and reduces airway responsiveness to histamine, methacholine, adenosine, and allergen.
Indications:
- Asthma
Adverse effects:
- Nausea (most common), vomiting, tremor, headache, central nervous system stimulation
- Palpitations, arrhythmias
Warnings/cautions:
- Hepatic impairment.
- Hypokalaemia risk.
- Hypertension.
- Hyperthyroidism.
- Peptic ulcers
Contraindications:
- People with porphyria.
- People with hypersensitivity to xanthines.
- Infants under 6 months of age
Interactions:
- Beta-2 agonists, corticosteroids, diuretics — hypokalaemia may be potentiated
- Lithium — excretion of lithium may be potentiated
- Fluvoxamine — can raise the plasma level of theophylline
Monitoring:
Urea and electrolyte levels (paying particular attention to potassium levels).
Check drug plasma levels:
Five days after starting oral treatment.
Routinely every 6–12 months. Check more regularly in older people or those with heart failure or hepatic impairment.
A 66-year-old man with a smoking history of one pack per day for the past 47 years presents with progressive shortness of breath and chronic cough, productive of yellowish sputum, for the past 2 years. On examination he appears cachectic and in moderate respiratory distress, especially after walking to the examination room, and has pursed-lip breathing. His neck veins are mildly distended. Lung examination reveals a barrel chest and poor air entry bilaterally, with moderate inspiratory and expiratory wheezing. Heart and abdominal examination are within normal limits. Lower extremities exhibit scant pitting oedema.
WHAT DOES HE HAVE?
Chronic Obstructive Pulmonary Disease
How do you manage COPD?
Conservative management: Smoking cessation - including offering nicotine replacement therapy, one-off pneumococcal vaccination
COPD Management
1. SABA (Salbutamol) continuous or SAMA (Ipratropium)
- LABA (Salmeterol) + LAMA (tiotropium)
- ICS + LABA
- ALL LAMA + LABA + ICS
Asthmatic features:
- SABA/SAMA
- LABA + ICS
- ADD LAMA
Antibiotics Rescue pack (for severe exacerbations)
For patients who remain breathless or have exacerbations despite using short-acting bronchodilators the next step is determined by whether the patient has ‘asthmatic features/features suggesting steroid responsiveness’
- any previous, secure diagnosis of asthma or of atopy
- substantial variation in FEV1 over time (at least 400 ml)
- substantial diurnal variation in peak expiratory flow (at least 20%)
DISCUSS SAMA (IPRATROPIUM) & LAMA (TIOTROPRIUM) ANTIMUSCARINIC CLINICAL PHARM
SAMA: IPRATROPIUM: used for short-term relief in mild COPD.
LAMA: prolonged binding to muscarinic receptors which lengthens the duration of bronchodilator effect.
MOA:
- Bind to the muscarinic receptor, where they act as a competitive inhibitor of acetylcholine.
- Antimuscarinics they increase heart rate and conduction; reduce smooth muscle tone, including in the respiratory tract and bladder; and reduce secretions from glands in the respiratory and GI tracts.
Drug examples: ipratropium, tiotropium
Indications:
- COPD
- Asthma
Adverse effects:
- Irritation of the respiratory tract with nasopharyngitis, sinusitis and cough
- GI disturbance including dry mouth and constipation, urinary retention, blurred vision and headaches.
Warnings/cautions
- ▴angle-closure glaucoma
- ▴arrhythmias
- ▴urinary retention
Contraindication:
- None
Interactions:
- Interactions are not generally a problem due to low systemic absorption.
Monitoring:
- Symptoms and reviewing peak flow measurements (asthma). You should enquire about side effects, particularly dry mouth.
- Inhaler technique
DISCUSS OXYGEN CLINICAL PHARM
Oxygen
MOA:
Mechanism of action:
- increases delivery of oxygen to the tissues, which in effect ‘buys time’ while the underlying disease is corrected
- This accelerates the diffusion of nitrogen out of the body.
- In CO poisoning, oxygen competes with CO to bind with haemoglobin and thereby shortens the half-life of carboxyhaemoglobin, returning haemoglobin to a form that can transport oxygen to tissues.
Indications:
- Increase oxygen in acute hypoxaemia
- Pneumothorax
- Carbon monoxide poisoning
Adverse reaction:
- Discomfort of nasal cannula
- Dry throat
- Hyperoxaemia
- Oxygen toxicity
Warnings (Cautions):
- COPD (risk of hypoxaemia and hypercapnia due to a rise in PaCO2 = Resp acidosis)
- Respiratory acidosis
- Hypoxia
- Depressed consciousness due to rise in PaCO2
- Fire risk due to combustion
Contraindication:
- None
Interactions:
None
Monitoring:
Frequent SpO2 monitoring is essential in all patients receiving oxygen for acute illness.
Arterial blood gas measurement is essential in patients with critical illness
DISCUSS MUCOLYTIC CLINICAL PHARM
MOA:
Carbocisteine serves to restore equilibrium between sialomucins and fucomucins, likely by intracellular stimulation of sialyl transferase enzyme, thus reducing mucus viscosity.
Indications:
- COPD
- Asthma
Adverse effects:
- Skin reactions including Stevens-Johnson syndrome and erythema multiforma
- Gastrointestinal bleeding and vomiting
Caution:
- People with a history of peptic ulceration or those taking concomitant medications known to cause gastrointestinal bleeding.
- People with a history of asthma or respiratory failure
Contraindications:
- People with active peptic ulceration.
- Women who are pregnant or breastfeeding.
Interactions:
- Combination of mucolytics with antitussives and/or substances that dry out secretions (atropinic)
- If oral antibiotics are required, these should be taken two hours before or after acetylcysteine.
DISCUSS ANTIHISTAMINES CLINICAL PHARM
Indications:
- Allergies, particularly hay fever (seasonal allergic rhinitis).
- Relief of itchiness (pruritus) and hives (urticaria), insect bites, infections (e.g. chickenpox)
- Treatment in anaphylaxis
- Used for nausea and vomiting
Adverse effects:
- Chlorphenamine cause sedation (via H1 receptors, has a role in the brain in maintaining wakefulness)
- Second gen: Loratadine, cetirizine and fexofenadine don’t cross the blood brain barrier, so they don’t have much side effects
Warnings/cautions: - Chlorphenamine - should be avoided in ▴severe liver disease. may precipitate hepatic encephalopathy. - Renal impairment. Prostatic hypertrophy. Urinary retention.
Contraindications:
- Sedating histamines avoided in first trimester pregnancy
- Non sedating Cetirizine caution to people with renal impairment
- Loratadine with caution to people with hepatic impairment
Interactions:
-The antihistamines mentioned here are not subject to any major drug interactions
