THE DEVICES – ‘Puffers’ and others
The most common type of inhaler that you will encounter is the Metered Dose Inhaler (MDI).
The MDI contains a small canister of inactive gas that propels a fixed amount of the drug for each puff. Each dose is released by pressing the top of the canister. The inhaler is quick to use, small, and convenient to carry. To be effective it needs good co-ordination to press the canister and breathe in at the same time. The gas used in all modern MDIs is harmless and eco-friendly.
MDIs are sometimes used with a Spacer Device. The spacer is tubular clear plastic box with a connection to the MDI at one end and a valve and mouthpiece at the other. The metered dose is puffed into the spacer and the patient then breathes in from the spacer mouthpiece. A number of breaths may be taken to get the full dose into the lungs. Using a spacer means that the pressing on the MDI does not have to be accurately timed to match the intake of breath.
Slightly larger than the normal MDI is the Breath-Activated MDI. This detects the intake of breath and automatically releases a measured dose of the drug. Breath-Activated MDIs are useful for patients who have difficulty in co-ordinated the acts required to use the basic model.
Dry Powder Inhalers (DPIs) do not use gas to puff out the drug, instead they rely on a strong intake of breath to pull into the longs the drug in a very fine powder form. The brand names you may come across include Turbohaler, Handihaler, Diskhaler and Accuhaler. Each type of Dry Powder Inhaler has a different method of measuring the dose. The Accuhaler comes ready with measured 60 doses; the Handihaler must be loaded with a small powder-filled capsule before each use. Even adults who have difficulty breathing in can manage to use these inhalers. Young children may not be able to cope with them.
Nebulisers are devices that take a drug as a liquid and from it create an aerosol – a vapour of microscopic droplets floating in the air. You breathe in the vapour either through a mouthpiece or by using a face mask. The normal process of breathing carries the drug into the lungs. Nebulisers come in many sizes – from large units which run on mains electricity to small battery-powered units which can fit in a pocket. In hospitals nebuliser attachments may be included in the oxygen supply line for those patients needing Oxygen Therapy.
INHALERS – The Drugs or Medications
The drug from an inhaler goes straight into the lungs. This means that only a small quantity of the drug is needed and very little of that gets into the rest of the body. Because of this side effects are rare or minor in nature.
The three main groups of inhaled drugs are Short Acting Bronchodilators (Relievers), Long Acting Bronchodilators and Steroids.
Short Acting Bronchodilators relax the tiny muscles in the airways (the bronchi) which then become wider and this usually gives quick relief. Drugs in this group include salbutamol and terbutaline. Different companies use their own brand names for these drugs, however most inhalers are either blue or grey.
Long Acting Bronchodilators work in the same way but as the name suggests the effect lasts much longer – up to twelve hours. Drugs in this group include formoterol and salmeterol. Some drugs known as anticholinergics have a relaxing effect on the smooth muscles in the lungs and this produces a long acting bronchodilatory effect (up to twentyfour hours). Drugs in this group include ipratropium and tiotropium.
Steroids are inhaled to prevent the airways becoming inflamed. Even taken daily, it can take up to two weeks for an inhaled steroid to reduce inflammation of the airways and up to six weeks to have maximum effect. After this period the use of steroid inhalers may be discontinued. Inhaled steroids can cause sore throats and therefore some people use a spacer device which helps eliminate this. Inhalers tend to be coloured orange, brown or red.
There are some non-steroids which are used as preventers but they are generally less effective than steroids.