S-Carboxymethylcysteine (carbocysteine or SCMC; also available in the lysinate form, SCMC-Lys) is a mucoactive drug, has antioxidant and anti-inflammatory properties. Carbocysteine has been recently recognized as an effective and safe treatment for the long-term management of COPD, able to reduce the incidence of exacerbations and improve patient quality of life. Moreover, carbocysteine was effective in counteracting some symptoms associated with cancer cachexia. Preclinical and clinical studies have demonstrated that the antioxidant and anti-inflammatory properties of carbocysteine are more important than mucolysis itself for its therapeutic efficacy. Therefore, carbocysteine may be able to reverse the oxidative stress associated with several chronic inflammatory diseases, such as cardiovascular diseases and neurodegenerative disorders.

Erdosteine is an antioxidant compound developed by Edmond Pharma and approved in Europe for the treatment of chronic bronchitis and COPD. Erdosteine has two thiol groups and is believed to act as a free radicals scavenger (through the formation of the active metabolite I, N-thiodiglycolylhomocysteine). Also the drug effect may be due to the inhibition of the activity of elastase enzyme and its interaction with mucosa. The drug got Orphan Drug designation by FDA for the treatment of bronchiectasis.

Bunazosin (E-643) is a quinazoline derivative with a1-adrenoceptor blocking activity. It has been clinically used both as a systemic antihypertensive as well as an ocular hypotensive drug. The major adverse effect associated with the use of bunazosin is orthostatic hypotension or its consequences (e.g. dizziness). Others adverse effects include headache, sweating, nausea, dry mouth, abdominal pain, diarrhea, and constipation. The effects of Bunazosin may be enhanced by diuretics and other antihypertensive agents and decreased by Rifampicin.

Etimizol was developed at the Institute of Experimental Medicine, St.Petersburg USSR in 1960s. Ethymisole, or 4,5-di(N-methylcarbamoyl)-1-ethyl-imidazole, is a cognitive enhancer and nootropic drug, the molecular target of which is a multifunctional protein kinase C K2 (casein kinase II). Etimizol improves short-term memory, strengthens adrenocorticotropic function of a hypophysis; excites respiratory center. It is indicated for the prevention of respiratory depression of various etiology, also etimizol is used for the treatment of astheno-depressive syndrome, arthritis, chronic obstructive pulmonary disease and bronchial asthma. Etimizol is marketed exclusively in Russia.

Doxofylline (7-(1, 3-dioxalan-2-ylmethyl) theophylline) is a novel xanthine bronchodilator which differs from theophylline in that it contains a dioxalane group in position 7. Doxofylline is indicated for the treatment of bronchial asthma, pulmonary disease with spastic bronchial component and Chronic Obstructive Pulmonary Disease (COPD). Doxofylline does not directly inhibit any of the known HDAC enzymes, and did not inhibit any phosphodiesterase (PDE) enzyme sub types or act as an antagonist at any of the known adenosine receptors, except for PDE2A(1), and adenosine A(2A) and only at the highest tested concentration (10(-4) M). Doxofylline has greatly decreased affinity towards adenosine A1 and A2 receptors, which explain its better safety profile. Moreover, it does not interfere with calcium influx into the cells nor antagonize calcium channel blockers. Doxofylline has been shown to be a more potent bronchodilator with fewer side effects than theophylline. This drug should not be administered together with other xanthine derivatives, including beverages and foods containing caffeine.

Bambuterol is an active precursor of the selective beta2-adrenergic agonist terbutaline. Bambuterol is the bis-N,N-dimethyl-carbamate of terbutaline. Bambuterol is a remarkably selective and potent inhibitor of cholinesterase. BAMBEC (Bambuterol hydrochloride) oral solution or tablets are indicated for the management of asthma, bronchospasm and/or reversible airways obstruction.

Oxitropium bromide (trade names Oxivent, Tersigan) is a bronchodilator indicated for asthma and chronic obstructive pulmonary disease. Oxitropium’s bronchodilation effect is similar to that of ipratropium bromide, but oxitropium is longer-lasting. The usual dose is 200 ug, 2–3 times daily. It blocks the muscarinic cholinergic receptors which mediate smooth muscle contraction in the airways. The manufacturer claims that regular use of oxitropium (200μg twice or three times daily) reduces the incidence of symptoms, including the need for night-time bronchodilators, and improves lung function in some patients; it is not intended for immediate symptom relief. Although widely used for many years (alone or in combination with short-acting beta agonists) for both maintenance treatment of stable disease and exacerbation of airway obstruction, Boehringer Ingelheim announced the discontinuation of Oxivent formulations at May 2004.

Fudosteine is a derivative of cysteine developed and approved in Japan for the treatment of such diseases as bronchial asthma, chronic bronchitis, pulmonary emphysema, bronchiectasis, pulmonary tuberculosis, pneumoconiosis, atypical mycobacterial disease and diffuse panbronchiolitis. Fudosteine acts as a mucoactive agent, enabling mucin secretion. Although exact mechanism of action is unknown, it is supposed that fudosteine inhibits MUC5AC expression.

Mecysteine is used as a mucolytic in respiratory disorders associated with productive cough. Mecysteine is known as a mucolytic agent, it breaks down mucus. It works by breaking some of the chemical bonds between the molecules in mucus. It is given orally in a usual dose of 200 mg three times daily before meals reduced to 200 mg twice daily after 6 weeks. A rapid clinical effect can be achieved by giving 200 mg four times daily for the first 2 days. Mecysteine has also been given by inhalation.

The anticholinergic agent Flutropium is a classic competitive antagonist of acetylcholine. In in vitro experiments it is more effective than atropine. A poor enteral absorption is to be expected; this can be concluded from the low relative effectiveness after oral administration. After local administration as an aerosol it is superior to atropine with regard to both effectiveness and duration of action. It is used in Japan to treat asthma and chronic obstructive pulmonary disease. Flutropium can be described as a preparation which is free of side effects.