How Does an Asthma Inhaler Work?

Types of Inhalers

According to the Mayo Clinic, there are two main types of inhalers. The metered dose inhaler uses a chemical propellant to carry a dose of medication into the asthmatic's lungs. The other type of inhaler, the dry powder inhaler, requires no propellant as the drug is sucked into the lungs by a quick, strong inhalation.

Metered Dose

Traditionally, the propellant of metered dose inhalers carries a specified dose out of the inhaler when the propellant canister is depressed. This type of inhaler requires the patient to coordinate their inhalation with the pressing of the propellant canister. A spacer chamber may be used between the inhaler and the patient's mouth to make this coordination easier. However, there are newer metered dose inhalers which do not require pushing the canister but instead are activated upon the patient's inhalation, completely eliminating the sometimes tricky push/breath coordination.

Dry Powder

Dry powdered inhalers can come in a variety of canisters, including disks, turbohalers, tube inhalers and accuhalers. These devices use cartridges or capsules that are ruptured or punctured by the inhaler device during activation (usually twisting a dial or pushing a button). The asthmatic then place their mouth on the mouthpiece and draw the medication into the lungs with a sharp inhalation.

Medications

The asthma medications delivered by the inhalers include bronchodilators, steroids and combinations of bronchodilators and steroids. Rescue inhalers are fast-acting bronchodilators that immediately relax the muscles of the respiratory tract, allowing for greater airflow. Maintenance inhalers deliver steroids that decrease the inflammation that can cause airway constriction. Some medications use a combination of a longer-acting bronchodilator and a steroid. Both maintenance and combination medications require days of regular use to be fully effective and are not effective in acute asthmatic flare-ups.

References

• Mayo Clinic
• FDA Industry Guidelines
• UK Patient Information

Resources

• Asthma and Allergy Foundation of America