SN6 SHORT NOTE 5M ★ High-yield

Describe the inhalational devices and the inhaled corticosteroids.

Pharmacology · 2nd Professional — Para-Clinical

WHY the Device Matters as Much as the Drug

Only about 10 to 20% of an inhaled dose reaches the lung even with perfect technique; most is swallowed or deposited in the oropharynx
Poor technique is extremely common — studies consistently find that most patients, and many prescribers, make at least one critical error. It is the single commonest reason inhaled treatment "fails"
Inhaled delivery achieves high airway concentrations with low systemic exposure, which is why inhaled corticosteroids can be given for years while oral steroids cannot

Types of Device

Device	How it works	Advantages	Limitations
Pressurised metered-dose inhaler (pMDI)	Propellant delivers a fixed dose; requires slow deep inhalation coordinated with actuation	Cheap, portable, multi-dose	Coordination is difficult, particularly for children and the elderly; high oropharyngeal deposition
PMDI with a spacer	The chamber holds the aerosol, allowing tidal breathing and removing the need for coordination	Greatly improves lung deposition; reduces oropharyngeal candidiasis and dysphonia; as effective as a nebuliser in most acute attacks	Bulky; needs regular washing and air-drying (not wiping, which creates static)
Dry powder inhaler (DPI)	Breath-actuated; requires a forceful deep inspiration to disaggregate the powder	No coordination needed; no propellant	Useless if inspiratory flow is inadequate — young children, the frail, and patients in a severe attack
Breath-actuated pMDI	Fires on inspiration	Removes the coordination problem	More expensive
Nebuliser	Converts solution to a mist inhaled by tidal breathing	Needs no cooperation; for the very young, very ill or very breathless	Slow, bulky, needs a power source; no better than a pMDI with spacer in most acute asthma; risk of infection from poorly cleaned equipment

CLINICAL PEARL

A spacer converts a difficult device into an easy one, and its benefits go beyond convenience. It removes the coordination problem, slows the aerosol so that less impacts on the throat. It reduces oral candidiasis and dysphonia, and at the same time increases lung deposition. In acute asthma, a pMDI with a spacer performs as well as a nebuliser for most patients, is faster, cheaper and carries no infection risk — and in a child a spacer with a face mask is the standard of care.

Inhaled Corticosteroids

Drugs — budesonide, fluticasone, beclometasone, ciclesonide (a prodrug activated in the lung, which reduces oropharyngeal effects), mometasone
The cornerstone of asthma control — the only class that treats the underlying inflammation, and the only one shown to reduce asthma deaths
Local adverse effects — oropharyngeal candidiasis, dysphonia (hoarseness from laryngeal myopathy), cough and throat irritation; all reduced by a spacer and by rinsing and spitting after use
Systemic effects, chiefly at high dose — adrenal suppression, reduced growth velocity in children (a small effect, largely recovered in final height), reduced bone density, cataract, glaucoma, skin thinning and easy bruising
In COPD they increase the risk of pneumonia, which is why they are reserved for those with frequent exacerbations or eosinophilia rather than given to everyone

Applied Aspects

Watch the patient use their inhaler at every review, and correct the technique; do not ask whether they can use it, since almost everyone says yes
Match the device to the patient — a dry powder inhaler is useless in a frail elderly patient with poor inspiratory flow, and a plain pMDI is useless in a child without a spacer
Prescribe a spacer with every pMDI corticosteroid, and teach washing in detergent and air-drying
Teach mouth rinsing after every corticosteroid dose — it prevents candidiasis and dysphonia and takes seconds
Avoid changing device type without retraining; a switch made for cost reasons without teaching commonly causes deterioration
Cost and availability shape practice in India — a pMDI with a home-made spacer (a modified plastic bottle has been shown to work well) is an effective and affordable option where commercial spacers are out of reach
Check the counter or float the canister to confirm the inhaler is not empty; patients frequently continue using a spent device and conclude their asthma has worsened

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