1. Controllers
2. Relievers

Controllers, as the name itself indicates, are drugs daily taken by patients, on a long term basis to keep asthma under clinical control chiefly through their anti-inflammatory effects. These agents are basically anti-inflammatory agents (inhaled/systemic corticosteroids) and long-acting bronchodilators (inhaled/oral β₂-agonists), being the former the most effective for long-term control of symptoms, improvement of lung-function and hyperresponsiveness reduction. In fact, inhaled glucocorticosteroids suppress airway inflammation and determine airway hyperresponsiveness decrease, therefore controlling and preventing asthma symptoms. On the other side, bronchodilators principally act to dilate the airways, since they induce airway smooth muscle relaxation, therefore reversing bronchoconstriction and symptoms of acute asthma. Alternative/additional controller medications are leukotriene modifiers (Montelukast, Pranlucast, Zileuton), methylxanthines (theophylline), cromones (sodium cromoglycate and nedocromil sodium), anti-IgE therapy (Omalizumab) and, although used only in particularly severe cases, additional systemic steroid sparing therapies.

Relievers are therapeutic agents that allow to quickly relieve bronchoconstriction and related acute symptoms, such as chest tightness, cough and wheezing, associated to the exacerbations of the disease. They are basically rapid-acting inhaled β₂-agonists. Oral therapy is rarely needed and reserved mainly for young children who cannot use inhaled therapy.

We will focus in particular on inhaled glucocorticosteroids (ICSs) and long-acting β₂-agonists (LABAs), which represent the most important controller medications in asthma therapy. The pharmacological management of the disease proposed by GINA guidelines, discussed later on in this chapter, will confirm these considerations.