context: Bronchodilators are medications that relax muscle bands that tighten around your airways. This opens the airway and lets more air move in and out of your lungs. That helps you breathe more easily. Bronchodilators also help remove mucus from your lungs. Open airways mean mucus can move more freely, too, and you can cough it up. Almost all people with asthma use a bronchodilator to help open their airways. Short-acting bronchodilators are used as a "quick relief" or "rescue inhalers", while long-acting bronchodilators can be used every day to control asthma -- along with an inhaled steroid. For treating asthma symptoms, there are three types of bronchodilators: beta-agonists, anticholinergics, and theophylline. You can get these bronchodilators as tablets, liquids, and shots, but the preferred way to take beta-agonists and anticholinergics is inhaling them. Short-acting bronchodilators are called quick-acting, reliever, or rescue medications. You might hear them called rescue inhalers. These bronchodilators relieve acute asthma symptoms or attacks very quickly by opening your airways. The rescue inhalers are best for treating sudden asthma symptoms. The action of inhaled bronchodilators starts within minutes after you inhale them and lasts for 2 to 4 hours. Short-acting bronchodilators are also used before exercise to prevent exercise-induced asthma. Short-acting bronchodilators can also be used in an asthma nebulizer in the form of a liquid to treat an asthma attack at home. Overuse of short-acting bronchodilators, whether it's a rescue inhaler, in tablets, or in liquid, is a sign of uncontrolled asthma that needs better treatment. If you need to use your short-acting bronchodilators more than twice a week, talk with your doctor about improving your asthma control therapy. Short-acting bronchodilator inhalers available in the United States include: Albuterol ( Accu Neb, Proair HFA, Proventil HFA, Ventolin HFA, also available as a generic solution for nebulizers) Metaproterenol , available as a generic solution for nebulizers Levalbuterol ( Xopenex HFA) Pirbuterol ( Maxair) Long-acting bronchodilators are used to provide control -- not quick relief -- of asthma. They should only be used with inhaled steroids for long-term control of asthma symptoms. You'll take a long-acting bronchodilator twice a day. Advair, Dulera, and Symbicort (a combination of a long-acting beta-agonist bronchodilator and an inhaled steroid) Salmeterol ( Serevent) Formoterol ( Foradil) Formoterol solution for nebulizers ( Perforomist) Long-acting beta-agonist bronchodilators raise the risk of death from asthma and should only be used as additional treatment for people who are using an inhaled steroid. For details, talk to your doctor and see the drugs' black-box warning. Bronchodilators can have side effects such as: Nervous or shaky feeling Higher heart rate or palpitations Upset stomach Trouble sleeping Muscle aches or cramps Anticholinergics are bronchodilators mainly used for treating COPD (chronic obstructive pulmonary disease, like emphysema) and asthma. Atrovent treats COPD and can be used off-label to treat asthma flares. You can get it as an inhaler and a nebulizer solution. Dry throat is the most common side effect. If the medication gets in your eyes, it can cause blurred vision for a short time. Tiotropium bromide ( Spiriva Respimat) is for people who have either asthma or COPD. It comes in an inhaler. Anyone over 6 can may use this medication once daily as a long-term asthma treatment. It's used for COPD flares and long-term treatment if inhaled bronchodilators don't help. Theophylline is a relatively weak but inexpensive bronchodilator that has a chemical similar to caffeine. It relaxes the smooth muscle that surrounds your airways. Theophylline is sold as a generic pill or under the brand names Theo-24 and Uniphyl. It's available as an oral (pill and liquid) or intravenous (through the vein) drug. You can also get it in short- and long-acting forms to prevent asthma symptoms, especially nighttime symptoms. It's not often used for asthma, though, because your doctor has to check your blood levels while you're on it to make sure you aren't getting too much. Side effects of theophylline include: Nausea and vomiting Diarrhea Stomachache Headache Rapid or irregular heartbeat Muscle cramps Jittery or nervous feeling Hyperactivity These side effects may also be a sign that you've taken too much medication. Your doctor will check levels of the drug in your blood to make sure you're getting the proper amount. Always tell your doctors if you take theophylline for asthma because certain medications, like some antibiotics, seizure medicines, and ulcer medicines, can interact with it. Make sure your doctor knows about any other medical conditions you may have. Some diseases and illnesses can change how your body responds to theophylline. And keep in mind that not only is smoking and exposure to cigarette smoke especially dangerous when you have asthma, it can also interfere with how your body responds to the medication. So it's best to avoid smoke and cigarette smoking.