Levalbuterol is the (R)-enantiomer of the drug substance racemic albuterol (salbutamol). Binding studies have demonstrated that (R)-albuterol binds to the beta2-adrenergic receptor with a high affinity, whereas (S)-albuterol binds with 100-fold less affinity than (R)-albuterol. Other evaluations have suggested that (R)-albuterol possesses the bronchodilatory, bronchoprotective, and ciliary-stimulatory properties of racemic albuterol, while (S)-albuterol does not contribute beneficially to the therapeutic effects of the racemate and was originally assumed to be inert. Xopenex (levalbuterol HCl) Inhalation Solution is indicated for the treatment or prevention of bronchospasm in adults, adolescents, and children 6 years of age and older with reversible obstructive airway disease.

Ipratropium (ipratropium bromide, ATROVENT® HFA) is a muscarinic antagonist structurally related to atropine but often considered safer and more effective for inhalation use. It is indicated for the maintenance treatment of bronchospasm associated with chronic obstructive pulmonary disease (COPD), including chronic bronchitis and emphysema. Ipratropium (ipratropium bromide, ATROVENT® HFA) is an anticholinergic (parasympatholytic) agent which, based on animal studies, appears to inhibit vagally-mediated reflexes by antagonizing the action of acetylcholine, the transmitter agent released at the neuromuscular junctions in the lung. Anticholinergics prevent the increases in intracellular concentration of Ca2+ which is caused by interaction of acetylcholine with the muscarinic receptors on bronchial smooth muscle.

Ipratropium (ipratropium bromide, ATROVENT® HFA) is a muscarinic antagonist structurally related to atropine but often considered safer and more effective for inhalation use. It is indicated for the maintenance treatment of bronchospasm associated with chronic obstructive pulmonary disease (COPD), including chronic bronchitis and emphysema. Ipratropium (ipratropium bromide, ATROVENT® HFA) is an anticholinergic (parasympatholytic) agent which, based on animal studies, appears to inhibit vagally-mediated reflexes by antagonizing the action of acetylcholine, the transmitter agent released at the neuromuscular junctions in the lung. Anticholinergics prevent the increases in intracellular concentration of Ca2+ which is caused by interaction of acetylcholine with the muscarinic receptors on bronchial smooth muscle.

Flunisolide is a synthetic corticosteroid. It is administered either as an oral metered-dose inhaler for the treatment of asthma or as a nasal spray for treating allergic rhinitis. Corticosteroids are naturally occurring hormones that prevent or suppress inflammation and immune responses. When given as an intranasal spray, flunisolide reduces watery nasal discharge (rhinorrhea), nasal congestion, postnasal drip, sneezing, and itching oat the back of the throat that are common allergic symptoms. Flunisolide is a glucocorticoid receptor agonist. The antiinflammatory actions of corticosteroids are thought to involve lipocortins, phospholipase A2 inhibitory proteins which, through inhibition arachidonic acid, control the biosynthesis of prostaglandins and leukotrienes. The immune system is suppressed by corticosteroids due to a decrease in the function of the lymphatic system, a reduction in immunoglobulin and complement concentrations, the precipitation of lymphocytopenia, and interference with antigen-antibody binding. Flunisolide binds to plasma transcortin, and it becomes active when it is not bound to transcortin. It is used for the maintenance treatment of asthma as a prophylactic therapy. Flunisolide is marketed as AeroBid, Nasalide, Nasarel.

Metaproterenol, also known as Orciprenaline, is a brochodilator that is FDA approved for the treatment of bronchial asthma and for reversible bronchospasm which may occur in association with bronchitis and emphysema. Metaproterenol Sulfate is a potent beta-adrenergic stimulator with a rapid onset of action. It is postulated that beta-adrenergic stimulants produce many of their pharmacological effects by activation of adenyl cyclase, the enzyme which catalyzes the conversion of adrenosine triphosphate to cyclic adenosine monosphosphate. Metaproterenol is a moderately selective beta(2)-adrenergic agonist that stimulates receptors of the smooth muscle in the lungs, uterus, and vasculature supplying skeletal muscle, with minimal or no effect on alpha-adrenergic receptors.

Cromolyn is a mast cell stabilizer. In vitro and in vivo animal studies have shown that cromolyn sodium inhibits the degranulation of sensitized mast cells, which occurs after exposure to specific antigens. Cromolyn sodium acts by inhibiting the release of histamine and SRS-A (slow-reacting substance of anaphylaxis) from the mast cell. Cromolyn is indicated in the management of patients with mastocytosis, prophylaxis (long-term control) of bronchial asthma, prevention of exercise-induced bronchospasm, prevention and treatment of seasonal and perennial allergic rhinitis The most frequently reported adverse reactions attributed to cromolyn sodium treatment were: throat irritation or dryness, bad taste, cough, wheeze, nausea.

Glycopyrrolate is a synthetic anticholinergic agent with a quaternary ammonium structure. Glycopyrrolate is a muscarinic competitive antagonist used as an antispasmodic, in some disorders of the gastrointestinal tract, and to reduce salivation with some anesthetics. Glycopyrrolate binds competitively to the muscarinic acetylcholine receptor. Like other anticholinergic (antimuscarinic) agents, it inhibits the action of acetylcholine on structures innervated by postganglionic cholinergic nerves and on smooth muscles that respond to acetylcholine but lack cholinergic innervation. These peripheral cholinergic receptors are present in the autonomic effector cells of smooth muscle, cardiac muscle, the sinoatrial node, the atrioventricular node, exocrine glands and, to a limited degree, in the autonomic ganglia. Thus, it diminishes the volume and free acidity of gastric secretions and controls excessive pharyngeal, tracheal, and bronchial secretions. Glycopyrrolate antagonizes muscarinic symptoms (e.g., bronchorrhea, bronchospasm, bradycardia, and intestinal hypermotility) induced by cholinergic drugs such as the anticholinesterases. The highly polar quaternary ammonium group of glycopyrrolate limits its passage across lipid membranes, such as the blood-brain barrier, in contrast to atropine sulfate and scopolamine hydrobromide, which are highly non-polar tertiary amines which penetrate lipid barriers easily. Glycopyrrolate is marketed under the brand names Robinul, Robinul Forte, Cuvposa. In October 2015, glycopyrrolate was approved by the FDA for use as a standalone treatment for Chronic obstructive pulmonary disease (COPD), as Seebri Neohaler.

Isoproterenol (trade names Medihaler-Iso and Isuprel) is a medication used for the treatment of bradycardia (slow heart rate), heart block, and rarely for asthma. Isoproterenol is a non-selective β adrenoreceptor agonist and TAAR1 agonist that is the isopropylaminomethyl analog of epinephrine. Isoprenaline's effects on the cardiovascular system (non-selective) relate to its actions on cardiac β1 receptors and β2 receptors on smooth muscle within the tunica media of arterioles. Isoprenaline has positive inotropic and chronotropic effects on the heart. β2 adrenoceptor stimulation in arteriolar smooth muscle induces vasodilation. Its inotropic and chronotropic effects elevate systolic blood pressure, while its vasodilatory effects tend to lower diastolic blood pressure. The overall effect is to decrease mean arterial pressure due to the β2 receptors' vasodilation. The adverse effects of isoprenaline are also related to the drug's cardiovascular effects. Isoprenaline can produce tachycardia (an elevated heart rate), which predisposes patients to cardiac arrhythmias.

Since its discovery as component of the tea leaf by Albert Kossel in 1888, the history of theophylline (CAS 58-55-9) has been a long and successful one. At the turn of the century, theophylline became less expensive due to chemical synthesis and was primarily used as diuretic in subsequent years. It was Samuel Hirsch who discovered the bronchospasmolytic effect of theophylline in 1992, however, despite this pioneering discovery theophylline continued to be used primarily as diuretic and cardiac remedy. The molecular mechanism of bronchodilatation is inhibition of phosphodiesterase(PDE)3 and PDE4, but the anti-inflammatory effect may be due to histone deacetylase (HDAC) activation, resulting in switching off of activated inflammatory genes. Theophylline is indicated for the treatment of acute exacerbations of the symptoms and reversible airflow obstruction associated with asthma and other chronic lung diseases, e.g., emphysema and chronic bronchitis.

Since its discovery as component of the tea leaf by Albert Kossel in 1888, the history of theophylline (CAS 58-55-9) has been a long and successful one. At the turn of the century, theophylline became less expensive due to chemical synthesis and was primarily used as diuretic in subsequent years. It was Samuel Hirsch who discovered the bronchospasmolytic effect of theophylline in 1992, however, despite this pioneering discovery theophylline continued to be used primarily as diuretic and cardiac remedy. The molecular mechanism of bronchodilatation is inhibition of phosphodiesterase(PDE)3 and PDE4, but the anti-inflammatory effect may be due to histone deacetylase (HDAC) activation, resulting in switching off of activated inflammatory genes. Theophylline is indicated for the treatment of acute exacerbations of the symptoms and reversible airflow obstruction associated with asthma and other chronic lung diseases, e.g., emphysema and chronic bronchitis.