An asthma inhaler is a medical device which delivers medication directly to the airways and lungs. While primarily used in the treatment of asthma, inhalers are also utilized to manage chronic obstructive pulmonary disease (COPD). There are a number of types of inhalers on the market, with numerous drug companies manufacturing asthma medications which can be delivered by inhaler.
One of the most common types of asthma inhaler is the metered dose inhaler. This device includes medication held under pressure in a canister, with a propellant. When the inhaler is activated, an aerosolized spray comes out of the mouthpiece of the inhaler. Patients can use the device alone or with a spacer, a chamber which is designed to regulate the inhalation of the aerosol to ensure that as much as possible reaches the lungs.
Metered dose inhalers are only good for a set number of doses of medication. Some have indicators to alert patients to when they need to be changed, but in most cases, patients may need keep track of how often the device is used to know how many doses are left. Patients can also determine how full the canister is by floating it in water, with various rules of thumb being used to measure fullness, depending on the product.
The propellants used in a metered dose asthma inhaler vary. By law, they cannot contain CFCs, which were once commonly used as propellants. Some contain vegetable ingredients such as corn, making it important for patients to disclose allergies to their pharmacists and doctors. If a pharmacist knows that a patient is allergic to corn, for example, it will affect whether or not a brand or generic inhaler should be used to fill a prescription.
Dry powder inhalers deliver a dry powder which patients must inhale. Such devices work by rupturing a small blister of powder when activated. Many have meters to show when the inhaler is empty, although patients can usually also tell because the inhaler does not admit any powder if it is emptied, unlike an aerosol asthma inhaler, which will emit a puff of propellant which could be mistaken for medication.
Another form of asthma inhaler is the nebulizer, which is used to deliver medicine in the form of a fine mist. Nebulizers are generally used in the treatment of asthma symptoms and breathing problems in hospital and clinic settings, although some patients with severe asthma maintain their own nebulizers so that they can perform breathing treatments at home.