Bronchodilator drugs work by relaxing the muscles in the airways to open breathing passages. There are three main types of bronchodilators: beta-adrenergic bronchodilators, anticholinergic bronchodilators, and xanthine derivatives. Each works through a different mechanism to dilate the bronchial airways. Common side effects among the drug types include dry mouth, headache, nausea, and difficulty breathing. Nurses monitor patients' vital signs and educate them on proper inhaler use when prescribing bronchodilators.