Prenoxdiazine under the brand name Libexin is used as an antitussive agent. It was shown, that the use of this drug for pregnant women with an unproductive cough could be beneficial.

trans-Sobrerol is a mucolytic known due its emplyment in therapy for respiratory diseases. In preclinical studies sobrerol, administered daily at the oral dose of 400 mg/rat, markedly decreased the monocrotaline-induced alterations and regulate the development of pulmonary hypertension. Treatment with sobrerol was well tolerated and significantly reduced frontal headache and rhinorrhoea, efficacy being confirmed by rhinomanometry.

Ambroxol, a substituted benzylamine, is an active metabolite of bromhexine, which is itself a synthetic derivative of vasicine, the active principle extracted from the plant species Adhatoda vasica. Ambroxol is an expectorant exerting mucokinetic properties, mucociliary activity, stimulation of surfactant production, anti-inflammatory and antioxidative actions and the local anaesthetic effect. Ambroxol was discovered at and has been manufactured by Dr. Karl Thomae GmbH, a division of Boehringer Ingelheim. The ambroxol patent is expired and the drug is available as a generic product from many different companies. Ambroxol was originally developed by Boehringer Ingelheim as a OTC therapy for respiratory disorders related to excessive mucus. Ambroxol's indication is secretolytic therapy in acute and chronic bronchopulmonary diseases associated with abnormal mucus secretion and impaired mucus transport. Boehringer Ingelheim markets the product under various brand names such as Mucosolvan® and Lasolvan®. Ambroxol was identified and found to be a pH-dependent, mixed-type inhibitor of glucocerebrosidase (GCase). Its inhibitory activity was maximal at neutral pH, found in the endoplasmic reticulum, and undetectable at the acidic pH of lysosomes. The pH dependence of Ambroxol to bind and stabilize the enzyme was confirmed. Ambroxol increases both the lysosomal fraction and the enzymatic activity of several mutant GCase variants. This profile of Ambroxol would allow to bind and stabilize GCase in the endoplasmic reticulum (thus preventing its degradation within endoplasmic reticulum), but without affecting GCase in the lysosomes (thus allowing it to degrade glucosylceramide). Indeed, studies showed that Ambroxol treatment significantly increased N370S and F213I mutant GCase activity and protein levels in fibroblasts originally obtained from Gaucher patients. Gaucher's disease is caused by the deficiency of glucocerebrosidase; ambroxol is a chaperone that acts by binding to and stabilising glucocerebrosidase. Zywie (formerly ExSAR Corporation) and Belrose Pharma are developing ambroxol hydrochloride (BEL 0218) for the treatment of type III Gaucher's disease. .

Eprazinone has been variously described as having mucolytic or expectorant properties as well as a direct relaxant action on bronchial smooth muscle and it suppress the excitation of cough center to stop coughing. It is usually used to treat symptoms of cough and phlegm caused by respiratory diseases such as cold, upper respiratory infection, bronchitis, and pneumonia The most commonly reported adverse reactions include loss of appetite, nausea/vomiting, stomach discomfort, diarrhea (including loose stool) and symptom of irritation.

NELTENEXINE, an amide derivative of ambroxol and thiophenecarboxylic acid, is a mucolytic agent. It is an elastase inhibitor used in the treatment of human lung diseases.

Pholcodine is an opioid that has been widely used worldwide since 1950 for the treatment of non-productive cough in children and adults. Illicit drug. Additionally Pholcodine is a marker for sensitization to neuromuscular blocking agents (NMBA) and is intended for use as a diagnostic tool in NMBA-induced anaphylaxis.

Bromhexine is used for conditions where there are a lot of thick mucus in the airways. Bromhexine acts on the mucus at the formative stages in the glands, within the mucus-secreting cells. Bromhexine disrupts the structure of acid mucopolysaccharide fibres in mucoid sputum and produces a less viscous mucus, which is easier to expectorate. In addition, bromhexine has antioxidant properties. Occasional, mild side effects include: a feeling of fullness in the stomach (bloatedness), diarrhea, dizziness, headache, indigestion, nausea, sweating and skin rashes. Bromhexine may increase the concentration of concurrently administered antibiotics in bronchial secretions. No clinically relevant interactions with other medications have been reported.

Oxeladin citrate is a cough suppressant, is a highly potent and effective drug used to treat all types of cough of various etiologies. Withdrawn from the Canadian, US, and UK markets in 1976 due to carcinogenicity. Oxeladine is a component of antitussive drug, Altussan, approved in Philippines.