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How Do Asthma Medicines Work?

Medically reviewed by: Elana Pearl Ben-Joseph, MD

How Does Asthma Affect the Airways?

People with asthma sometimes have trouble breathing. Everyday stuff, like animal dander or tobacco smoke, can make it worse and trigger a flare-up. During a flare-up, it’s hard for air to get through the airways. They fill with mucus and the muscles around the airways can tighten up too.

Luckily, medicine can help.

How Do Asthma Medicines Work?

Asthma medicines generally work in two ways:

  • Some medicines work right away to relax the muscles around the airways and open them, providing quick relief of symptoms. That's why they're often called quick-relief, "fast-acting," or "rescue" medicines. They are usually inhaled (breathed in) using an inhaler device or a nebulizer. The most commonly used medicines for the quick relief of symptoms are bronchodilators (such as albuterol).
  • Other medicines work over time to ease inflammation, which reduces swelling of the airways and limits mucus production. This can help to prevent symptoms. These medicines often called long-term control,"controller," or "maintenance" medicines. These usually need to be taken every day, even when a person feels fine and has no symptoms.

    Some people with mild asthma might use anti-inflammatory medicines only during times of increased symptoms instead of every day. These are also usually inhaled, but some types are swallowed as a pill or liquid. A variety of medicines can ease inflammation, but inhaled corticosteroids are used most often. They're a safe and proven form of asthma treatment and are different from performance-enhancing steroids used by some athletes.

Some people will get both kinds of medicines from one inhaler device. They might need to use a “combination” inhaler every day, with added doses from it when they have symptoms. Someone with mild asthma might use a combination inhaler only for quick relief when they have symptoms, or before they exercise. Your health care team will help you figure out which inhaler is best, and how and when you should use it.

For a more severe flare-up, doctors might prescribe oral (taken by mouth) steroids for 5–7 days. These work more quickly to reduce inflammation when inhaled medicines aren’t quite enough. If someone has a flare-up that's severe enough to need treatment in the ER, they might get medicines by injection.

What Else Should I Know?

When asthma medicines are given through an inhaler, it's important to use a spacer, which helps deliver as much medicine as possible into the airways.

Always keep the medicine you use for quick symptom relief with you. That means at home, at school, at the mall, at sports practice, and even on vacation. Talk with your doctor about how often you need to use it. If it's too often, the doctor also might prescribe a daily anti-inflammatory medicine to help prevent asthma flare-ups.

Your doctor will decide which type of medicine you need based on your symptoms and how often they happen. Tell your doctor about any concerns or changes in your symptoms. That will help them find the best treatment and make updates when needed.

For many people, the medicine they use and its dosage will change over time and as their symptoms change.

Medically reviewed by: Elana Pearl Ben-Joseph, MD
Date reviewed: September 2023