Asthma

• Asthma


  A chronic obstructive lung disease, which can be controlled but not cured
• Asthma diagnosis


  • Based on history, physical examination, considering other diagnoses, and documenting variable airflow limitation (spirometry – pre-post bronchodilator variability)

  
• Asthma triggers


  • House dust mites
  • Mould
  • Pets
  • Pollen
  • Cigarette smoke
  • Exercise
  • Chemicals
  • Respiratory Infections
  • Weather (e.g., thunderstorms)
  • Medications
  • Occupational exposures
• Asthma pathophysiology


  Repeated infections/exposures disrupt airway epithelial barrier, leading to danger signaling, chemokine secretion, recruitment of immature dendritic cells, antigen presentation, stimulation of Th2 cells, and eosinophilic inflammation
• Asthma is the most common chronic condition in children globally

  
• Most asthma-related deaths occur in low- and lower-middle-income countries, where under-diagnosis and under-treatment is a challenge
• Asthma trajectories


  Variable pathways – early onset (mostly atopic), post puberty – resolution/new development, adult onset –late onset asthma

  
• Asthma may be a result of gene-environment interactions that occur as early as in-utero
• Risk factors that impact onset, development, progression of asthma


  • Genetic factors
  • Gut-lung axis – microbiome development
  • Immune function maturation
  • Lower lung function at birth
  • Respiratory infections in early childhood (Human Rhinovirus (HRV) and Respiratory Syncytial Virus (RSV)
  • Ongoing repeated respiratory infections in early childhood
  • Allergen sensitisation
  • Exposure to particulate matter, traffic related air pollution (TRAP), volatile organic compounds (VOC), ETS etc.
  • Obesity
• Remodelling process


  Damaged epithelium secretes autocrine growth factors, similar to developing foetal lung
• Fahy JV: 'Type 2 inflammation in asthma — present in most, absent in many'

  
• The diagnosis of asthma is based on: history, physical examination, considering other diagnoses, and documenting variable airflow limitation (spirometry – pre-post bronchodilator variability)

  
• Asthma Control


  • Good control
  • Partial control
  • Poor control
• Factors associated with increased risk of flare-ups include: poor control, previous flare-ups, other respiratory conditions, poor lung function, difficulty perceiving airflow limitation, eosinophilic (Th2) airway inflammation, exposure to cigarette smoke/substances, socioeconomic disadvantage/access, mental illness
• Factors associated with increased risk of life-threatening asthma


  • ICU admission (ever)
  • 2 hospitalisations or 3 ED visits for asthma in past year
  • Hospitalisation or ED visit for asthma in the past month
  • High short-acting beta2 agonist use
  • History of delayed presentation to hospital during flare-ups or of sudden acute flare ups
  • Cardiovascular disease
  • Sensitivity to an unavoidable
  • Experience of side-effects of OCS use
  • Lack of written asthma action plan
• Bronchodilators (Relievers)


  • Short acting beta agonists (SABAs)
  • Long-acting beta agonists (LABAs)
  • Short or Long-acting muscarinic antagonists (SAMA/LAMA)
• Anti-inflammatory agents (Preventers)


  • Inhaled corticosteroids (ICS)
  • Leukotriene receptor antagonists (LTRA)
  • Targeted biologic agents
• Bronchoconstriction is caused through the inflammation process – therefore anti-inflammatory medications have to be the mainstay of treatment. Bronchodilators address only one symptom manifestation
• There are stepped approaches to adjusting asthma medication in adults/adolescents, children aged 6-11 years, and children aged 1-5 years
• Short acting beta 2 agonists (SABAs)


  Reliever medications available over-the-counter (Schedule 3)
• Salbutamol


  • Formulation type: pressurised metered dose inhaler or pMDI and Autohaler
  • Formulation strength: 100 Pgs/puff x 200 doses
  • Time to action: 1-2 minutes
  • Elimination half life: 2.7-5 hours
  • Dose: 1-2 puffs (100-200 Pgs) every 4-6 hours ONLY when needed or 5-15 minutes pre-exercise
• Inappropriate inhalation technique can lead to systemic absorption of salbutamol
• Salbutamol precautions


  • Risk of angle-closure glaucoma, especially if used with ipratropium
  • Range of precautions for non-inhaled routes (CVD, thyroid disease, diabetes)
  • Safe to use in pregnancy/breastfeeding, especially in inhaled form
  • Subject to conditions and restrictions for use in sport
• Salbutamol side effects


  • Skeletal muscle tremor
  • Peripheral arteriole dilation
  • Tachycardia
  • Headache
  • Nausea
  • Insomnia
  • Hyperactivity in children
  • Paradoxical bronchospasm
  • Potentially serious hypokalemia
• pMDI usage steps


  1. Remove cap

  2. Shake inhaler

  3. Exhale out

  4. Place in mouth, press actuator and start inhaling at the same time

  5. Hold breath

  6. Exhale out

  7. Wait 1 minute before using again

  8. Replace cap after use
• Spacer usage steps


  1. Assemble spacer

  2. Remove inhaler cap

  3. Hold inhaler upright and shake well

  4. Insert inhaler upright into spacer

  5. Put mouthpiece between teeth without biting and close lips to form good seal

  6. Breathe out gently

  7. Hold spacer level and press down firmly on canister once

  8. Breathe in slowly and deeply or take 4-5 normal breaths through mouthpiece

  9. Hold breath for about 5 seconds or as long as comfortable

  10. Remove spacer from mouth

  11. Breathe out gently away from mouthpiece

  12. Remove inhaler from spacer

  13. If an extra dose is needed, wait 1 minute and then repeat

  14. Replace cap and disassemble spacer
• Terbutaline


  • Reliever medication available over-the-counter (Schedule 3)
  • Formulation: Dry Powder Inhaler (DPI)
  • Formulation strength: 500 Pgs/puff x 120 doses
  • Time to action: 5-30 minutes
  • Elimination half life: excreted mainly unchanged in urine, practically all eliminated after 72 hours
  • Dose: 1–3 inhalations (500–1500 micrograms) when required, or 5–15 minutes before exercise
• Inappropriate inhalation technique can lead to systemic absorption or no dose with terbutaline
• Terbutaline precautions


  • Risk of angle-closure glaucoma, especially if used with ipratropium
  • Range of precautions for non-inhaled routes (CVD, thyroid disease, diabetes)
  • Safe to use in pregnancy/breastfeeding, especially in inhaled form
  • Not permitted in sport but check current status
• Terbutaline inhaler usage steps


  1. Take cover off

  2. Prime for first time use

  3. Actuate by turning right then left till a click is heard

  4. Exhale out normally away from mouthpiece

  5. Place mouth on mouthpiece and inhale fast and deep

  6. Remove mouthpiece from mouth and breath as long as comfortable

  7. Exhale away from mouthpiece

  8. Replace cover
• Reliever medications


  Schedule 3
• SEs lower in inhalation route
• Inhaled salbutamol may rarely precipitate acute angle-closure glaucoma


  Especially if used with ipratropium
• Pregnancy/breastfeeding


  Safe to use esp in inhaled form
• Key Steps in Using Dry Powder Inhalers- Turbuhalers


  1. Take cover off

  2. Prime for first time use

  3. Whilst keeping upright, actuate by turning right then left till a click is heard

  4. Exhale out normally away from mouthpiece

  5. Place mouth on mouthpiece and inhale fast and deep (long)

  6. Remove mouthpiece from mouth and breath as long as comfortable

  7. Exhale away from mouthpiece

  8. Replace cover
• Salbutamol vs terbutaline


  • No clinical difference in effect
  • For S4 versions terbutaline is no longer subsidised by PBS
  • Dry powder inhalers may need a higher inspiratory flow generation (though most people even with severe asthma etc. can use these inhalers)
  • Dry powder inhalers more environmentally friendly – lower carbon footprint
• Key Roles for Pharmacists (S3 Context)


  • Check asthma control (how?)
  • Check if patient has been prescribed preventers (if Sx > 2 per month)
  • Check patient is adherent to preventers (how?)
  • Check level of SABA usage (no of puffs/day or cannisters bought per year) – info gathering/pharmacy records if you record sales
  • Check if patient knows appropriate technique for using their SABA inhaler
  • Check if there may be comorbid conditions (AR, OSA, GORD – refer if needed)
  • Check if patient has an asthma action plan
• Increased risk of severe flare-ups in patients using as-needed SABAs in the absence of inhaled corticosteroids or with poor adherence to inhaled corticosteroids
• SABA use issues


  • Patients with well-controlled asthma do not need to use their reliever on more than 2 days per week
  • Recent asthma symptom control is based on symptoms over the previous 4 weeks
  • Overuse is associated with increased risk of severe flare-ups and asthma death
  • If a patient uses SABAs frequently, asthma should be comprehensively reviewed to identify problems (e.g., poor adherence to inhaled corticosteroids, poor technique, triggers) and referred to physician for review

  
• Signs that someone may be having an exacerbation


  • experiencing increasing wheezing, cough, chest tightness or shortness of breath
  • waking often at night with asthma symptoms
  • needing to use your blue/grey reliever again within 3 hours