Chronic obstructive pulmonary disease (COPD) is a disease of the lungs that is usually caused by smoking. People with COPD are short of breath. They sometimes have spasms of the lung's airways (bronchial tubes), and they cough and wheeze. Symptoms and lung damage slowly get worse over time. Most patients also have bouts of worsening of symptoms. We call these bouts exacerbations. Doctors use several drugs to treat COPD. Many come in the form of inhalers or puffers. In an inhaler, the drugs are in solutions in small pressurized cans that have pumps. Patients put the pump's mouthpiece in their mouth and push the pump as they start to inhale deeply. They then hold their breath for about 10 seconds so that the airways absorb the medicine. The standard metered-dose inhaler releases a fixed dose of medicine in aerosol form. Examples of drug inhalers include tiotropium (known by the brand name Spiriva), salmeterol (known by the brand name Serevent), and a combination of fluticasone and salmeterol (known by the brand name Advair). Drugs in these inhalers have different actions. Tiotropium and salmeterol expand (dilate) the bronchial tubes. Fluticasone, a steroid, fights inflammation.