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.

Ephedrine (l-form) is an alkaloid, which was initially purified from Ephedra plant. The extract form Ephedra has been used in China for medicinal purposes for several thousand years. Ephedrine acts as an agonist at alpha- and beta-adrenergic receptors and indirectly causes the release of norepinephrine from sympathetic neurons. The drug crosses the blood brain barrier and stimulates the central nervous system. Ephedrine products are now banned in many countries, as they are a major source for the production of the addictive compound methamphetamine. FDA has approved ephedrine only for the treatment of clinically important hypotension occurring in the setting of anesthesia.

Indacaterol is an ultra-long-acting beta-adrenoceptor agonist developed by Novartis. It was approved by the European Medicines Agency (EMA) under the trade name Onbrez Breezhaler on November 30, 2009, and by the United States Food and Drug Administration (FDA), under the trade name Arcapta Neohaler, on July 1, 2011. It needs to be taken only once a day, unlike the related drugs formoterol and salmeterol. It is licensed only for the treatment of chronic obstructive pulmonary disease (COPD) (long-term data in patients with asthma are thus far lacking). It is delivered as an aerosol formulation through a dry powder inhaler.

Amlexanox is an ant allergic drug, clinically effective for atopic diseases, especially allergic asthma and rhinitis. Amlexanox as a topical paste is a well-tolerated treatment of recurrent aphthous ulcers. Recurrent aphthous ulcer (RAU) is the most prevalent oral mucosal disease in humans, estimated to affect between 5% and 50% of the general population. The mechanism of action by which amlexanox accelerates healing of aphthous ulcers is unknown. In vitro studies have demonstrated amlexanox to be a potent inhibitor of the formation and/or release of inflammatory mediators (histamine and leukotrienes) from mast cells, neutrophils and mononuclear cells. Given orally to animals, amlexanox has demonstrated anti-allergic and anti-inflammatory activities and has been shown to suppress both immediate and delayed type hypersensitivity reactions. The relevance of these activities of amlexanox to its effects on aphthous ulcers has not been established. Amlexanox inhibits chemical mediatory release of the slow-reacting substance of anaphylaxis (SRS-A) and may have antagonistic effects on interleukin-3. When cells are under stress, they release an inactive form of human fibroblast growth factor 1 (FGF-1), a potent mitogen (entity that causes mitosis). Amlexanox binds to FGF1, increasing its conformational stability, sterically blocking Cu(2+) induced oxidation which normally leads to activation of FGF-1. This drug has been discontinued in the U.S

Nedocromil is a medication considered as mast cell stabilizer used to treat itching associated with allergic conjunctivitis. Nedocromil has been shown to inhibit the in vitro activation of, and mediator release from, a variety of inflammatory cell types associated with asthma, including eosinophils, neutrophils, macrophages, mast cells, monocytes, and platelets. Nedocromil inhibits activation and release of inflammatory mediators such as histamine, prostaglandin D2 and leukotrienes c4 from different types of cells in the lumen and mucosa of the bronchial tree. These mediators are derived from arachidonic acid metabolism through the lipoxygenase and cyclo-oxygenase pathways. The mechanism of action of nedocromil may be due partly to inhibition of axon reflexes and release of sensory neuropeptides, such as substance P, neurokinin A, and calcitonin-geneñrelated peptides. The result is inhibition of bradykinin-induced bronchoconstriction. Nedocromil does not possess any bronchodilator, antihistamine, or corticosteroid activity. Nedocromil is indicated for the treatment of itching associated with allergic conjunctivitis.

Beclometasone dipropionate or beclomethasone dipropionate is sold under the brand name Qvar among others. Beclomethasone dipropionate is a corticosteroid demonstrating potent anti-inflammatory activity. The precise mechanism of corticosteroid action on asthma is not known. Corticosteroids have been shown to have multiple anti-inflammatory effects, inhibiting both inflammatory cells (e.g., mast cells, eosinophils, basophils, lymphocytes, macrophages, and neutrophils) and release of inflammatory mediators (e.g., histamine, eicosanoids, leukotrienes, and cytokines). These anti-inflammatory actions of corticosteroids may contribute to their efficacy in asthma. Beclomethasone dipropionate is a prodrug that is rapidly activated by hydrolysis to the active monoester, 17 monopropionate (17-BMP). Beclomethasone 17 monopropionate has been shown in vitro to exhibit a binding affinity for the human glucocorticoid receptor, which is approximately 13 times that of dexamethasone, 6 times that of triamcinolone acetonide, 1.5 times that of budesonide and 25 times that of beclomethasone dipropionate. The clinical significance of these findings is unknown. Studies in patients with asthma have shown a favorable ratio between topical anti-inflammatory activity and systemic corticosteroid effects with recommended doses of QVAR. Beclometasone dipropionate was first patented in 1962 and used medically in 1972. Common side effects with the inhaled form include respiratory infections, headaches, and throat inflammation. Serious side effects include an increased risk of infection, cataracts, Cushing’s syndrome, and severe allergic reactions. Long term use of the pill form may cause adrenal insufficiency. The pills may also cause mood or personality changes. The inhaled form is generally regarded as safe in pregnancy. Beclometasone is mainly a glucocorticoid.

Pirbuterol (trade name Maxair) is a short-acting β2 adrenoreceptor agonist with bronchodilating action used in the treatment of asthma. The pharmacologic effects of beta-adrenergic agonist drugs, including pirbuterol, are at least in proof attributable to stimulation through beta-adrenergic receptors of intracellular adenyl cyclase, the enzyme which catalyzes the conversion of adenosine triphosphate (ATP) to cyclic-adenosine monophosphate (c-AMP). Increased c-AMP levels are associated with relaxation of bronchial smooth muscle and inhibition of release of mediators of immediate hypersensitivity from cells, especially from mast cells. Pirbuterol is used in asthma for reversal of acute bronchospasm, and also as a maintenance medication to prevent future attacks. It should be used in patients 12 years of age and older with or without concurrent theophylline and/or inhaled corticosteroid. After inhalation of doses up to 800 μg (twice the maximum recommended dose) systemic blood levels of pirbuterol are below the limit of assay sensitivity (2–5 ng/ml). A mean of 51% of the dose is recovered in urine as pirbuterol plus its sulfate conjugate following administration by aerosol. Pirbuterol is not metabolized by catechol-O-methyltransferase.

Bitolterol is a beta 2-adrenergic agonist. Since it in itself is biologically inactive, bitolterol is considered a pro-drug. When administered it is activated within the lung by esterase hydrolysis to the active compound colterol catecholamine N-t-butyl-arterenol. Bitolterol was marked under the name tornalate and was indicated to prevent and treat of reversible bronchospasm associated with asthma or chronic obstructive pulmonary diseases. But that drug was withdrawn from the market by Elan Pharmaceuticals in 2001.

Isoetharine is a beta-2 adrenergic receptor agonist, which was developed by Max Bockmuhl, Gustav Erhart and Leonhard Stein at the Hochst laboratories of I.G. Farbenindustrie in 1934. By binding to beta-2 adrenergic receptors on bronchial cell membranes, isoetharine increases the level of cAMP and thus stimulates the relaxation of smooth-muscle cells, stabilizes mast cells and inhibits histamine release. Isoetharine was approved by FDA for the symptomatic relief of bronchiospasms in patients with chronic bronchitis or emphysema (aerosol and solution for inhalation), however, later on the drug was discontinued.

Triamcinolone is a long-acting synthetic corticosteroid primarily used for their anti-inflammatory effects in disorders of many organ systems. Triamcinolone diacetate injectable suspension is indicated for intramuscular use as follows: Allergic States Control of severe or incapacitating allergic conditions intractable to adequate trials of conventional treatment in asthma, atopic dermatitis, contact dermatitis, drug hypersensitivity reactions, perennial or seasonal allergic rhinitis, serum sickness, transfusion reactions. Bullous dermatitis herpetiformis, exfoliative erythroderma, mycosis fungoides, pemphigus, severe erythema multiform (Stevens-Johnson syndrome). Endocrine Disorders Primary or secondary adrenocortical insufficiency, congenital adrenal hyperplasia, hypercalcemia associated with cancer, nonsuppurative thyroiditis. To tide the patient over a critical period of the disease in regional enteritis and ulcerative colitis. Hematologic Disorders Acquired (autoimmune) hemolytic anemia, Diamond-Blackfan anemia, pure red cell aplasia, selected cases of secondary thrombocytopenia. Trichinosis with neurologic or myocardial involvement, tuberculous meningitis with subarachnoid block or impending block when used with appropriate ant tuberculous chemotherapy. For palliative management of leukemia’s and lymphomas. Nervous System Acute exacerbations of multiple sclerosis; cerebral edema associated with primary or metastatic brain tumor, or craniotomy. Sympathetic ophthalmia, uveitis and ocular inflammatory conditions unresponsive to topical corticosteroids. To induce diuresis or remission of proteinuria in idiopathic nephrotic syndrome or that due to lupus erythematosus. Berylliosis, fulminating or disseminated pulmonary tuberculosis when used concurrently with appropriate ant tuberculous chemotherapy, idiopathic eosinophilic pneumonias, symptomatic sarcoidosis. As adjunctive therapy for short-term administration in acute gouty arthritis; acute rheumatic carditis. The anti-inflammatory actions of corticosteroids are thought to involve lipocortins, phospholipase A2 inhibitory proteins that, through inhibition of arachidonic acid, control the biosynthesis of prostaglandins and leukotrienes. Firstly, however, these glucocorticoids bind to the glucocorticoid receptors, which translocate into the nucleus, bind DNA (GRE), and change genetic expression both positively and negatively. 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.