Openers: bronchodilators
Around each airway is a ring of smooth muscle. When it tightens — bronchospasm — the tube narrows and breathing gets harder. Bronchodilators relax that muscle, opening the airway. There are two main switches. Beta-agonists act on β2 receptors to relax muscle quickly: a short-acting beta-agonist (SABA, the classic blue reliever) works within minutes for a few hours, while a long-acting beta-agonist (LABA) lasts 12–24 hours for daily control. Separately, antimuscarinics block the nerve signal that constricts airways and clears mucus.
Calmers: inhaled corticosteroids
In asthma, the core problem is inflammation in the airway lining. An inhaled corticosteroid (ICS) is the main controller: taken every day, it gradually quietens the inflammation, reduces eosinophilic inflammation, and prevents attacks. It is preventive, not a rescue — it will not relieve sudden breathlessness on the spot, and skipping it on good days lets inflammation creep back. Because it is inhaled at low doses, whole-body steroid side effects are uncommon; the main local effects are hoarseness and oral thrush, reduced by using a spacer and rinsing the mouth.
The roles differ by disease. In asthma, ICS is the foundation and bronchodilators support it. In COPD, long-acting bronchodilators are the foundation, and ICS is added mainly for people with frequent flare-ups or eosinophilic inflammation — used carefully, because in COPD steroids can slightly raise pneumonia risk.
Combinations and the bigger picture
Many people end up on more than one drug. A combination inhaler packs two or three of these into a single device — for example ICS plus LABA, or LABA plus antimuscarinic, or all three together. This improves convenience and adherence, since one device replaces two or three. Modern asthma care often uses a single ICS-LABA inhaler for both daily control and relief, so the controller and reliever are never separated.
A simple way to sort inhaled drugs: RELIEVERS (act fast, short-lived) --------------------- SABA e.g. salbutamol/albuterol onset minutes, ~4-6 h (sometimes SAMA, a short-acting antimuscarinic) -> for sudden symptoms / before exercise CONTROLLERS (taken daily, prevent symptoms) ---------- ICS inhaled corticosteroid calms inflammation LABA long-acting beta-agonist 12-24 h dilation LAMA long-acting antimuscarinic 12-24 h dilation -> taken every day, even when feeling well COMBINATIONS (controllers in one device) ------------- ICS + LABA common in asthma LABA + LAMA common in COPD ICS + LABA + LAMA "triple therapy" Rule of thumb: asthma -> ICS is the foundation COPD -> long-acting bronchodilator(s) are the foundation