Respiratory Therapeutics - Asthma

Question 1

Asthma is a.. and Asthma can be divided into:

Answer 1

common chronic inflammatory condition of the lung airways.

Asthma can be divided into:
-Extrinsic - implying it has a definite external cause
-Intrinsic - when no causative agent can be found
Note, these can overlap.

Question 2

Asthma symptoms and characteristics

Answer 2

• Cough
• Wheeze
• Chest tightness
• Shortness of breath – often worse at night

There are 3 characteristics:

Airflow limitation – this is usually reversible spontaneously or with treatment
Airway hyperresponsiveness - to a range of stimuli
Inflammation of the bronchi with eosinophils, T lymphocytes, and mast cells with associated plasma exudation, oedema, smooth muscle hypertrophy, matrix deposition, mucus plugging and epithelial damage

Question 3

Airway wall remodeling can cause

Answer 3

Airway wall remodeling can cause irreversible airflow limitation in chronic asthma. This may involve large and small airways and mucus impaction.

Question 4

Asthma Causes and triggers

Answer 4

• Environmental exposure to allergen e.g. grass pollen, domestic pets
• Occupational sensitizers
• Atmospheric pollution
• Drugs oral (e.g. NSAIDs) and/or topical
• Viral infections
• Cold air
• Emotion
• Exercise
• Diet
• Irritant dusts, vapour and fumes

Occupational sensitizers / Occupational Asthma
Non-IgE related e.g. isocyanates (e.g. polyurethane varnishes, wood dust)

IgE related e.g. latex, proteolytic enzymes, allergens from animals and insects, antibiotics

Question 5

WHO strategy for prevention and control of asthma

Answer 5

WHO’s programme objectives are:

• surveillance to map the magnitude of asthma, analyse its determinants and monitor trends, with emphasis on poor and disadvantaged populations;
• primary prevention to reduce the level of exposure to common risk factors, particularly tobacco smoke, frequent lower respiratory infections during childhood, and air pollution (indoor, outdoor, and occupational exposure); and
• improving access to cost-effective interventions including medicines, upgrading standards and accessibility of care at different levels of the health care system.

Question 6

Inflammation

Key cells involved:

Answer 6

Mast cells: increased in epithelium, smooth muscle and mucous glands in asthma. Generate and release mediators, release cytokines, chemokines and growth factors.

Eosinophils: large numbers in bronchial wall and secretions of asthmatics. They are involved in the release of mediators that are toxic to the epithelial cells.

Dendritic cells and lymphocytes: dendritic cells have a role in initial uptake and presentation of allergens to lymphocytes.

Question 7

asthma Diagnosis is made using:

Answer 7

• Clinical assessment and history, signs and symptoms
• Lung function tests
• Probability
• Atopic status
• Reversibility testing
• Airway responsiveness
• Other investigations

Question 8

Peak expiratory flow (PEF)

Answer 8

Peak expiratory flow is an indicator for monitoring deterioration and improvement in asthma. Tables are used to calculate an expected peak expiratory flow rate based on age, gender and height. The PEF is reported as a percentage of predicted or best for the patient.

Question 9

Drug treatment – Chronic Asthma

Answer 9

• Bronchodilators
• Corticosteroids
• Cromoglicate and related therapy (chromones)
• Leukotriene receptor antagonists
• Theophyllines
• Omalizumab

Question 10

SABAs (SHort beta 2 agonists) inhaled

Answer 10

Salbutamol, terbutaline (these should be rarely used alone

Question 11

Inhaled corticosteroids.

Answer 11

• Beclometasone dipropionate
• Budesonide
• Fluticasone propionate
• Ciclesonide
• Mometasone furoate

Beclometasone dipropionate (BDP) CFC-free pressurised MDIs (Qvar® and Clenil Modulite®) are not interchangeable and should be prescribed by brand name (MHRA/CHM advice July 2008)

Question 12

Inhaled corticosteroids - side effects

Answer 12

Fewer systemic effects than oral corticosteroids

• High dose used for prolonged periods can induce adrenal suppression
• Associated with adrenal crisis and coma in children, excessive doses should be avoided
• Provide steroid card to patient on high doses and written advice to consider corticosteroid replacement during episode of stress e.g. intercurrent illness or surgery
• High dose – lower respiratory tract infections including pneumonia, in older patients with COPD
• Bone mineral density reduced with long term high dose
• Prolonged high dose – risk of glaucoma
• Cataracts
• Hoarseness, candidiasis of mouth or throat (usually with high dose) – consider spacer devices
• Children – possible dose dependent growth failure: monitor growth of children on an annual basis (See BTS guidelines for full information).

Question 13

LABAs (Long acting beta agonists)

Answer 13

For patients with asthma, LABAs must be used with inhaled corticosteroids, see CHM advice below.

CHM advice – long acting beta2agonists (LABAs)

To ensure safe use, the CHM has advised that for the management of chronic asthma, LABAs should:

• Be added only if regular use of standard-dose inhaled corticosteroids has failed to control asthma adequately
• Not be initiated in patients with rapidly deteriorating asthma
• Be introduced at a low dose and the effect properly monitored before considering dose increase
• Be discontinued in the absence of benefit
• Not be used for the relief of exercise-induced asthma symptoms unless regular inhaled corticosteroids are also used
• Be reviewed as clinically appropriate: stepping down therapy should be considered when good long-term asthma control has been achieved
• Patients should be advised to report any deterioration in symptoms following initiation of treatment with a LABA.

Question 14

LABA / corticosteroid combo products

Answer 14

• Budesonide and formoterol Symbicort Turbohaler® 100/6, 200/6, 400/12
• Fluticasone propionate and salmeterol, Seretide Evohaler® 50, 125, 250 Seretide Accuhaler® 100, 250, 500. The number denotes the amount of fluticasone propionate in micrograms per dose. Accuhalers® contain 50micrograms salmeterol per dose, Evohalers® contain 25micrograms salmeterol per dose
• Beclometasone dipropionate and formoterol fumarate CFC-free pMDI Fostair® (prescribe by brand name)
• Fluticasone propionate and formoterol fumarate, Flutiform®
• Fluticasone furoate and novel long-acting beta2 agonist: vilanterol (Relvar Ellipta®)
• Use of combination inhalers guarantees LABA is not taken without inhaled steroid

Question 15

Cromoglicate and related therapy

Answer 15

Sodium cromoglicate, nedocromil sodium

• Mode of action not completely understood
• May be of benefit in allergic asthma however response should be monitored to observe to assess improvement
• No value in treatment of acute attacks of asthma
• Can cause paradoxical bronchospasm

Nedocromil
-Evidence of efficacy in children aged 5 – 12 years.

Sodium Cromoglicate

• In general, prophylaxis is less effective than prophylaxis with corticosteroid inhalations
• Sodium cromoglicate is of some benefit in adults and is effective in children aged 5-12
• Can prevent exercise-induced asthma. Note that exercise-induced asthma may reflect poor asthma control and the patient should be re-assessed.

Question 16

Leukotriene receptor antagonists

Answer 16

Montelukast, zafirlukast

• Block the effects of cysteinyl leukotrienes in the airways
• Effective in asthma when used alone or with an inhaled corticosteroid
• May be of benefit in exercise- induced asthma and in those with concomitant rhinitis
• Less effective in those with severe asthma who are also receiving high doses of other drugs
• Side effects - include Churg-Strauss syndrome, rare
• Zafirlukast – counsel parents on recognising symptoms of hepatic disorder (nausea, vomiting, malaise)

Question 17

Monoclonal antibodies

Answer 17

Omalizumab (Xolair®)
Monoclonal antibody that binds to immunoglobulin E (IgE)
Used as additional therapy in individuals with proven IgE-mediated sensitivity to inhaled allergens, whose severe persistent allergic asthma cannot be controlled adequately with high-dose inhaled corticosteroid together with a LABA.
The appropriate dose and dosing frequency of Omalizumab is determined by baseline IgE (IU/ml), measured before the start of treatment, and body weight (kg)
Given by subcutaneous injection every 2 or 4 weeks
Initiated by physicians in specialist centres experienced in treatment of severe persistent asthma
Side effects include Churg-Strauss syndrome (rarely), hypersensitivity reactions
NICE technology appraisal guidance 278

Gives guidance on when omalizumab can be initiated in adults and children over 6 years
States criteria to be fulfilled for initiation, continuation and discontinuation.

Mepolizumab
‘As an add-on to optimised standard therapy, is recommended as an option for treating severe refractory eosinophilic asthma in adults, only if: the blood eosinophil count is 300 cells/microlitre or more in the previous 12 months and the person has agreed to and followed the optimised standard treatment plan and has had 4 or more asthma exacerbations needing systemic corticosteroids in the previous 12 months or has had continuous oral corticosteroids of at least the equivalent of prednisolone 5 mg per day over the previous 6 months and the company provides the drug with the discount agreed in the patient access scheme. 1.2 At 12 months of treatment: stop mepolizumab if the asthma has not responded adequately or continue treatment if the asthma has responded adequately and assess response each year. An adequate response is defined as: at least 50% fewer asthma exacerbations needing systemic corticosteroids in those people with 4 or more exacerbations in the previous 12 months or a clinically significant reduction in continuous oral corticosteroid use while maintaining or improving asthma control.’

Question 18

Antimuscarinics

Answer 18

Tiotropium
Note the recent (2014) licensing of tiotropium in asthma: Spiriva Respimat is indicated as an add-on maintenance bronchodilator treatment in adult patients with asthma who are currently treated with the maintenance combination of inhaled corticosteroids (≥800 µg budesonide/day or equivalent) and long-acting β2 agonists and who experienced one or more severe exacerbations in the previous year.

Question 19

stepwise management

Answer 19

Stepping up

• Before initiating a new drug therapy, practitioners should:
• Check adherence with existing therapies
• Check inhaler technique
• Eliminate trigger factors

Stepping down

• Important to review patient regularly as treatment is stepped down
• Various factors to consider when deciding which drug to step down first
• Patients should be maintained on the lowest possible dose of inhaled steroid

Question 20

treatment of acute asthma

Answer 20

• Oxygen
• Bronchodilators
• Oral/IV corticosteroids
• Consider a dose of magnesium sulphate Intravenous
• IV Aminophylline

Question 21

Asthma in preg and breastfeeding

Answer 21

Asthma in pregnancy
Patients should be monitored closely and counselling should be provided. The risk of harm to the foetus from severe or chronically under-treated asthma outweighs any small risk from the medications used to control asthma.

Use beta2agonists as normal
Use inhaled steroids as normal
Use oral theophylline / aminophylline and IV aminophylline as normal. Check levels in acute severe asthma and in those critically dependent on therapeutic theophylline levels
Use steroid tablets as normal when indicated
Continue leukotriene receptor antagonists in women who have demonstrated, prior to pregnancy, significant improvement not achievable with other medications
Use chromones as normal

Asthma in pregnancy and breastfeeding

Management during labour should be in accordance with guidelines. Care needs to be taken when selecting medication to treat asthma in breast feeding mothers.

Question 22

Asthma and other meds

Answer 22

NSAIDs and beta-blockers are two groups of drugs that require careful consideration in asthmatic patients - as per information provided below. NSAIDs inhibit arachidonic acid metabolism via the cyclo-oxygenase (COX) pathway preventing synthesis of certain prostaglandins. It is suggested there is reduced production of PGE2 which in some genetically susceptible individuals, induces the overproduction of cysteinyl leukotrienes by eosinophils, mast cells and macrophages.

Beta-blockers:

• Bronchospasm
• Beta-blockers, including those considered to be cardioselective, should usually be avoided in patients with a history of asthma, bronchospasm or a history of obstructive airways disease. However, when there is no alternative, a cardioselective beta-blocker can be given to these patients with caution and under specialist supervision. In such cases the risk of inducing bronchospasm should be appreciated and appropriate precautions taken.

Question 23

Adult and child over 5 years

Step 1—Mild intermittent asthma

Answer 23

Start inhaled short-acting beta2 agonist (such as salbutamol or terbutaline sulfate) as required
Patients using more than one short-acting bronchodilator inhaler a month should have their asthma urgently assessed and action taken to improve poorly controlled asthma. Inhaled ipratropium bromide, (or, if over 12 years, short-acting beta2 agonist tablets and syrup, or theophylline) also act as short-acting bronchodilators but inhaled short-acting beta2 agonists are preferred.

Move to step 2 if the patient presents with any one of the following features; is using an inhaled beta2 agonist three times a week or more, being symptomatic three times a week or more, experiencing night-time symptoms at least once a week, or has had an asthma attack in the last 2 years.

Question 24

Adult and child over 5 years

Step 2—Regular preventer therapy

Answer 24

Consider adding regular inhaled standard-dose corticosteroid (alternatives to inhaled corticosteroid are leukotriene receptor antagonists, theophylline, inhaled sodium cromoglicate, or inhaled nedocromil sodium, but are less effective)

Beclometasone dipropionate and budesonide are approximately equivalent in clinical practice although there may be variations with different drug delivery devices. Fluticasone and mometasone furoate provide equal clinical activity to beclometasone dipropionate and budesonide at half the dosage.

Start the inhaled corticosteroid at a dose appropriate to severity of disease and adjust to the lowest effective dose at which control of asthma is maintained. Inhaled corticosteroids (except ciclesonide) should be initially taken twice daily, however, the same total daily dose can be considered once a day if good control is established.

In children, administration of high doses of inhaled corticosteroids may be associated with systemic side-effects, including growth failure, reduced bone mineral density, and adrenal suppression, see individual drug monographs for monitoring information.

If asthma is not adequately controlled, move to step 3.

Question 25

Adult and child over 5 years | Step 2—Regular preventer therapy (Note, inhaled standard-dose corticosteroid:)

Answer 25

- Adult and child over 12 years: 200–800 micrograms/day beclometasone dipropionate or equivalent - Child 5–12 years: 200–400 micrograms/day beclometasone dipropionate or equivalent

Question 26

Adult and child over 5 years | Step 3—Initial add-on therapy

Answer 26

Consider adding a regular inhaled long-acting beta2 agonist (LABA) such as formoterol fumarate or salmeterol (or, in adults only, indacaterol or olodaterol) to be used in conjunction with an inhaled corticosteroid (see also CHM advice for formoterol fumarate and salmeterol) If the patient is gaining some benefit from addition of a LABA but control is inadequate then continue the LABA and increase dose of inhaled corticosteroid to top end of inhaled standard-dose corticosteroid range. If there is no response to the LABA, discontinue and increase dose of inhaled corticosteroid. If control is still inadequate, start a trial of either a leukotriene receptor antagonist (montelukast, or zafirlukast if over 12 years) or modified-release theophylline.

Question 27

Adult and child over 5 years | Step 4—Persistent poor control

Answer 27

Consider the following options: Increase dose of inhaled corticosteroid (a spacer should be used), or Add a leukotriene receptor antagonist, modified-release theophylline, or modified-release oral beta2 agonist (caution in patients already taking a LABA) Note, increased inhaled corticosteroid dose Adult and child over 12 years: up to 2000 micrograms/day beclometasone dipropionate or equivalent Child 5–12 years: up to 800 micrograms/day beclometasone dipropionate or equivalent Beclometasone dipropionate and budesonide are approximately equivalent in clinical practice although there may be variations with different drug delivery devices. Fluticasone and mometasone furoate provide equal clinical activity to beclometasone dipropionate and budesonide at half the dosage. Before proceeding to step 5, refer patients with inadequately controlled asthma to specialist care.

Question 28

Adult and child over 5 years | Step 5- Continuous or frequent use of oral corticosteroids

Answer 28

Add a regular oral corticosteroid (prednisolone, as single daily dose) at lowest dose to provide adequate control; continue high-dose inhaled corticosteroid (in exceptional cases, this may exceed licensed doses)

Question 29

Child under 5 years | Step 1—Mild intermittent asthma

Answer 29

Inhaled short-acting beta2 agonist (such as salbutamol or terbutaline sulfate) as required. Children identified to be using more than one short-acting bronchodilator inhaler a month should have their asthma urgently assessed and action taken to improve poorly controlled asthma. Move to step 2 if the child presents with any one of the following features; is using an inhaled beta2 agonist three times a week or more, being symptomatic three times a week or more, experiencing night-time symptoms at least once a week.

Question 30

Child under 5 years | Step 2—Regular preventer therapy

Answer 30

Consider adding regular standard-dose inhaled corticosteroid If the child is unable to take an inhaled corticosteroid, a leukotriene receptor antagonist (such as montelukast) is an effective first-line preventer Note, inhaled standard-dose corticosteroid: Child under 5 years: 200–400 micrograms/day beclometasone dipropionate or equivalent Beclometasone dipropionate and budesonide are approximately equivalent in clinical practice although there may be variations with different drug delivery devices. Fluticasone provides equal activity to beclometasone dipropionate and budesonide at half the dosage. Start inhaled corticosteroid at a dose appropriate to severity of disease and adjust to the lowest effective dose at which control of asthma is maintained. Administration of high doses of inhaled corticosteroids in children may be associated with systemic side-effects, including growth failure, reduced bone mineral density and adrenal suppression. If asthma is not adequately controlled, move to step 3.

Question 31

Child under 5 years | Step 3—Initial add-on therapy

Answer 31

In children 2–5 years, add a leukotriene receptor antagonist if not added during step 2. If a leukotriene receptor antagonist was added at step 2, reconsider addition of standard-dose inhaled corticosteroid In children under 2 years, consider proceeding to step 4

Question 32

Child under 5 years | Step 4—Persistent poor control

Answer 32

Refer child to respiratory paediatrician

Question 33

Stepping down

Answer 33

Patient should be maintained at the lowest possible dose of inhaled corticosteroid. Reductions should be considered every three months, decreasing the dose by approximately 25–50% each time. Reduce the dose slowly as patients deteriorate at different rates.

Question 34

Exercise-induced asthma

Answer 34

For most patients, exercise-induced asthma is an illustration of poorly controlled asthma and regular treatment including inhaled corticosteroids should therefore be reviewed. If exercise is a specific problem in patients already taking inhaled corticosteroids who are otherwise well controlled, consider adding either a leukotriene receptor antagonist, a long-acting beta2 agonist, an oral beta2 agonist, sodium cromoglicate or nedocromil sodium, or theophylline. An inhaled short-acting beta2 agonists used immediately before exercise is the drug of choice.

Question 35

Management of acute asthma in Adults | Levels of severity

Answer 35

The nature of treatment required for the management of acute asthma depends on the level of severity, described as follows: -Moderate acute asthma Increasing symptoms Peak flow > 50-75% best or predicted No features of acute severe asthma ``` -Severe acute asthma Any one of the following: Peak flow 33-50% best or predicted Respiratory rate ≥ 25/min Heart rate ≥ 110/min Inability to complete sentences in one breath ``` ``` -Life-threatening acute asthma Any one of the following, in a patient with severe asthma: Peak flow < 33% best or predicted Arterial oxygen saturation (SpO2) < 92% Partial arterial pressure of oxygen (PaO2) < 8 kPa Normal partial arterial pressure of carbon dioxide (PaCO2) (4.6–6.0 kPa) Silent chest Cyanosis Poor respiratory effort Arrhythmia Exhaustion Altered conscious level Hypotension ``` -Near-fatal acute asthma Raised PaCO2, requiring mechanical ventilation with raised inflation pressures, or both

Question 36

Management of acute asthma in adults

Answer 36

Patients with moderate asthma should be treated at home or in primary care according to response to treatment, while patients with severe or life-threatening acute asthma should start treatment as soon as possible and be admitted to hospital immediately following initial assessment. Supplementary oxygen should be given to all hypoxaemic patients with acute severe asthma to maintain a SpO2 level between 94–98%. First-line treatment for acute asthma is a high-dose inhaled short-acting beta2 agonist (salbutamol or terbutaline sulfate) given as soon as possible. A pressurised metered dose inhaler with spacer device is preferred in patients with non-life-threatening acute asthma. Whereas, in patients with life-threatening acute asthma, a beta2 agonist administered by an oxygen-driven nebuliser is recommended. If the response to an initial dose of short-acting beta2 agonist is poor, consider continuous nebulisation with an appropriate nebuliser. Intravenous beta2 agonists are reserved for those patients in whom inhaled therapy cannot be used reliably. In all cases of acute asthma, patients should be prescribed an adequate dose of oral prednisolone once daily for at least 5 days or until recovery. Parenteral hydrocortisone or intramuscular methylprednisolone are alternatives in patients who are unable to take oral prednisolone. Nebulised ipratropium bromide may be combined with a nebulised beta2 agonist in patients with acute severe or life-threatening asthma or in those with a poor initial response to beta2 agonist therapy to provide greater bronchodilation. There is some evidence that magnesium sulfate has bronchodilator effects. A single intravenous dose of magnesium sulfate may be considered in patients with severe acute asthma (peak flow < 50% best or predicted) who have not had a good initial response to inhaled bronchodilator therapy [unlicensed use]. In an acute asthma attack, intravenous aminophylline is not likely to produce any additional bronchodilation compared to standard therapy with inhaled bronchodilators and corticosteroids. However, in some patients with near-fatal or life-threatening acute asthma with a poor response to initial therapy, intravenous aminophylline may provide some benefit. Magnesium sulfate by intravenous infusion or aminophylline should only be used after consultation with, or on the recommendation of, senior medical staff.

Question 37

Child over 2 years | Levels of severity

Answer 37

-Moderate acute asthma Able to talk in sentences Arterial oxygen saturation (SpO2) ≥ 92% Peak flow ≥ 50% best or predicted Heart rate ≤ 140/minute in children aged 2–5 years; heart rate ≤ 125/minute in children over 5 years Respiratory rate ≤ 40/minute in children aged 2–5 years; respiratory rate ≤ 30/minute in children over 5 years -Severe acute asthma Can’t complete sentences in one breath or too breathless to talk or feed SpO2 < 92% Peak flow 33–50% best or predicted Heart rate > 140/minute in children aged 2–5 years; heart rate > 125/minute in children aged over 5 years Respiratory rate > 40/minute in children aged 2–5 years; respiratory rate > 30/minute in children aged over 5 years ``` -Life-threatening acute asthma Any one of the following in a child with severe asthma: SpO2 < 92% Peak flow < 33% best or predicted Silent chest Cyanosis Poor respiratory effort Hypotension Exhaustion Confusion ```

Question 38

Management of acute asthma in children over 2 years

Answer 38

Following initial assessment, supplementary high flow oxygen should be given to all children with life-threatening acute asthma or SpO2 < 94% to achieve normal saturations of 94–98%. First-line treatment for acute asthma is an inhaled short-acting beta2 agonist (salbutamol or terbutaline sulfate) given as soon as possible, ideally via a metered dose inhaler and spacer device in mild to moderate acute asthma. Children with severe or life-threatening acute asthma should be transferred to hospital urgently. In all cases of acute asthma, children should be prescribed an adequate once daily dose of oral prednisolone. Treatment for up to 3 days is usually sufficient, but the length of course should be tailored to the number of days necessary to bring about recovery. Intravenous hydrocortisone should be reserved for severely affected children who are unable to retain oral medication. Nebulised ipratropium bromide can be combined with beta2 agonist treatment for children with severe or life-threatening acute asthma or in those with a poor initial response to beta2 agonist therapy to provide greater bronchodilation. Consider adding magnesium sulfate to nebulised salbutamol and ipratropium bromide in the first hour in children with a short duration of acute severe asthma symptoms presenting with an oxygen saturation less than 92%. Children with continuing severe asthma despite frequent nebulised beta2 agonists and ipratropium bromide plus oral corticosteroids, and those with life-threatening features, need urgent review by a specialist with a view to transfer to a high dependency unit or paediatric intensive care unit (PICU) to receive second-line intravenous therapies. In a severe asthma attack where the child has not responded to initial inhaled therapy, early addition of a single bolus dose of intravenous salbutamol may be an option. Continuous intravenous infusion of salbutamol, administered under specialist supervision with continuous ECG and electrolyte monitoring, should be considered in children with unreliable inhalation or severe refractory asthma. Aminophylline may be considered in children with severe or life-threatening acute asthma unresponsive to maximal doses of bronchodilators and corticosteroids. Aminophylline is not recommended in children with mild to moderate acute asthma. Intravenous magnesium sulfate has been used for acute asthma [unlicensed use] although its place in management is not yet established.

Question 39

Child under 2 years

Answer 39

Inhaled short-acting beta2 agonists are the initial treatment of choice for acute asthma in children under 2 years. For mild to moderate acute asthma attacks, a metered-dose inhaler with a spacer and mask is the optimal drug delivery device. In a hospital setting, consider oral prednisolone daily for up to 3 days, early in the management of severe asthma attacks. For more severe symptoms, inhaled ipratropium bromide in combination with an inhaled beta2 agonist is also an option.

Question 40

Metered dose inhalers (MDIs) | adv and disadv

Answer 40

Advantages - Portable and compact - Treatment time is short - No drug preparation required - No contamination of contents - Dose-dose reproducibility high Disadvantages - Coordination of breathing and actuation needed - Device actuation required - High pharangeal deposition - Upper limit to unit dose content - Remaining doses difficult to determine - Potential for abuse - Not all medications available

Question 41

MDI + holding chamber, reverse-flow spacer or spacer | adv and disadv

Answer 41

Advantages Reduces need for patient co-ordination Reduces pharyngeal deposition Disadvantages Inhalation can be more complex for some patients Can reduce dose available if not used properly More expensive than MDI alone Less portable than MDI alone Integral actuator devices may alter aerosol properties compared to native actuator

Question 42

Dry powder inhalers (DPI) | adv and disadv

Answer 42

``` Advantages Breath actuated Less patient coordination required Propellant not required Small and portable Short treatment time Dose counters in most newer designs ``` ``` Disadvantages May require moderate to high inspiratory flow Some units are single dose Can result in high pharyngeal deposition Not all medications available ```