Inhalers are hand-held, portable devices that deliver medicine directly to the lungs. A New England Journal of Medicine-published study showed that higher amounts of medicine can reach the airways and side effects are fewer with inhalers than with medicines delivered via the bloodstream. Various inhaler devices are available that vary in technique and the amount of drug distributed to the lungs. The major types of inhalers are metered dose inhalers, nebulizers and dry powder inhalers.
Metered Dose Inhaler, or MDI
MDIs consist of a curved plastic mouthpiece and a pressurized canister containing medicine. Typically, the medicine is discharged by pushing the canister into the mouthpiece. Some MDIs are breath-activated to release medicine, a National Institutes of Health report says. The only MDI available with a built-in counter that displays how many doses remain is Ventolin HFA. For other MDIs, the user manually tracks the number of doses to determine when the medicine is low.
Spacers enhance the MDI's key function of getting medicine to the lower airways. A spacer is a tube placed on the mouthpiece of an MDI which holds the released medicine, allowing the user more time to inhale slowly. The benefits are less medicine being lost into the air or left on the back of the throat, so more medicine reaches the airways. Some MDIs have a built-in spacer, while others are used with a separate spacer.
Nebulizers
A nebulizer turns asthma medicine into a fine mist that is breathed in through a mouthpiece or mask covering the nose and mouth. Breathing through the mouthpiece is normal and no skills are required to use the nebulizer. According to the American Academy of Allergy Asthma and Immunology, nebulizers are useful for those who cannot use inhalers or people with more severe asthma who need larger doses of medicine.
Dry Powder Inhaler, or DPI
Using a dry powder inhaler differs substantially from an MDI. With these inhalers, the medicine is released by breathing in a more powerful and quicker breath. DPIs are also not used with spacers. According to the NIH, most children under 4 years old may not generate a powerful enough inhalation to activate the DPI. Available types include a dry powder tube inhaler, a powder disk inhaler and a single-dose dry powder disk inhaler.
Other devices
For those unable to use a standard MDI or dry powder inhaler, other inhaler devices are available. One option is a metered dose inhaler with a face mask. The American College of Chest Physicians states that this is particularly useful for infants or small children. The face mask attaches to a standard metered dose inhaler with a spacer and fits tightly over the nose and mouth to optimize the amount of medicine reaching the airways.
Asthma Medicines Available with Inhalers
MDIs and nebulizers are available with beta2-agonists, corticosteroids, cromolyn, and anticholinergic medicines. The DPIs are used for beta2-agonists, corticosteroids, and anticholinergic medicines. According to the NIH, some medicines such as cromolyn, most inhaled corticosteroids, and the beta2-agonist salmeterol are only effective when they are inhaled and therefore are not available in other forms of delivery.
References
- "New England Journal of Medicine"; Control of Asthma by Aerosols; MT. Newhouse, et al; October 1986
- National Institutes of Health: National Asthma Education and Prevention Program Expert Panel Report 3-Guidelines for the Diagnosis and Management of Asthma
- Ventolin HFA: Ventolin HFA Counts for You
- American Academy of Allergy Asthma and Immunology: Tips to Remember- Inhaled Asthma Medications
- American College of Chest Physicians: Using Your MDI With a Spacer and Mask
