There are four basic types of inhaler available, each with specific advantages and disadvantages, making them suitable for certain groups of patients. A controlled dose is emitted as a spray when the device is activated. The advantages of MDIs are that they are quick to use, small and portable, and relatively cheap. However, there are several disadvantages with MDIs. Research has shown that around 50 per cent of patients using an MDI experience problems1.
Perfect technique is essential for correct drug delivery.
This can be quite difficult to achieve, requiring good co-ordination between activating the device and inhalation. Because of this, it is considered that MDIs are generally unsuitable for children under the age of about six and for many elderly patients or those with problems such as arthritis, which can impair manual dexterity. The education and subsequent reinforcement required for MDIs is considerable. Another problem with MDIs is that the cold jet of propellant can irritate the throat, which in turn causes coughing. Newer types of MDIs, which are breath-actuated, release the drug when the patient breathes in.