Normethadone is a derivate of opioid analgetic methadone, used as component of antitussive drops in Canada. Illicit drug.

Clobutinol is a cough suppressant that is withdrawn from the US and EU markets. Clobutinol was used for the short-term treatment of irritable, non-productive cough (a ‘dry' cough where the patient does not cough up any phlegm or mucus). Medicines containing clobutinol have been available since 1961 and were authorised in a number of Member States. Clobutinol-containing medicines were available in Austria, Belgium, the Czech Republic, Germany, Greece, Finland and France. They include tablets, oral solutions, syrups and solutions for injection, and were available over-the-counter in many Member States. Clobutinol was available as generic and branded medicines, most of which were marketed by Boehringer Ingelheim under the trade name Silomat. Studies in 2004 had indicated that clobutinol has the potential to prolong the QT interval. In 2007, Clobutinol was determined to cause cardiac arrhythmia in some patients.

Morclofon is an antitussive agent.

Levodropropizine is a non-opioid cough suppressant whose peripheral antitussive action may result from its modulation of sensory neuropeptide levels within the respiratory tract. Levodropropizine exerts its antitussive effect through an inhibitory action at the level of the airway sensory nerves and it has been shown to be able to inhibit in vitro the release of neuropeptides from C-fibers. Levodropropizine is an effective antitussive drug both in children and adults, showing statistically significant better outcomes vs. central antitussive drugs in terms of overall efficacy in reducing cough intensity, frequency and night awakenings. After oral administration, Levodropropizine is absorbed from the intestine, undergoes the first-pass metabolism and reaches peak plasma concentrations approximately 90 to 120 minutes after administration. Levocloperastine undergoes extensive biotransformation and is widely distributed throughout the body. Levocloperastine can cross the placental barrier (although to a moderate extent), but there is no evidence of accumulation, and is eliminated in the form of metabolites mainly in the faeces and to a lesser degree in the urine. The pharmacological effects of Levodropropizine were confirmed in large-scale clinical trials, non-blind or comparative. In the 10 trials reported here, oral Levodropropizine caused a rapid remission (after the first day of treatment) in cough symptoms (intensity and frequency of a daytime cough and disturbed night-time sleep) in all groups of patients. In children, the improved sleep quality resulted in a significant reduction in irritability and an overall improvement in their quality of life. Importantly, in adult patients with COPD, Levodropropizine reduced the frequency and intensity of dry unproductive cough without adversely influencing the beneficial effects of underlying treatment. In clinical trials, Levodropropizine was generally well tolerated, with mild and transient nausea the only adverse event reported. There was no evidence of central adverse events with Levodropropizine.

Dimemorfan is a nonnarcotic antitussive drug. The antitussive action of dimemorfan appears to be directly on the cough center in the medulla.

Benproperine (Cofrel) is a cough suppressant. It is used for symptomatic relief of cough. Cofrel is 2-4 times as potent as codeine in suppressing cough in animals. It acts peripherally by blocking afferent sensory nerve impulses originating from receptors in the lungs and pleura.

Nepinalone is a new alchilaminate derivative of β-tetralone, which possess a non-opioid antitussive activity. Nepinalone racemus exerted a significant antitussive activity and both L- and D-isomers confirmed to possess a significant dose-correlated antitussive effect with better trend of activity for D-isomer, but not statistically significant. It was predicted to act via sigma receptors. Occasionally, episodes of gastric intolerance have been reported and rapidly receded when treatment was stopped. The use of doses higher than those recommended could cause drowsiness.

Domiodol is an iodinated organic compound. Domiodol had a marked cilio-excitatory effect, but did not affect experimental asthma in guinea-pigs or the respiratory resistance of anesthetized dogs. In a placebo-controlled crossover study, domiodol significantly increased the volume of secretions in chronic bronchitis subjects. This was deemed beneficial because patients were able to most easily cough up the mucus. Mucolytic treatment may be helpful in the post-operative treatment of laryngectomized patients with permanent tracheostomy. In addition, domiodol proved effective in reducing the symptoms of infection of the lower respiratory tract and in improving the consistency of mucus in children.

Isoaminile is a cough suppressant that acts by influencing the cough centre.

Zipeprol is disubstituted piperazine that is marketed as a non-opioid antitussive in Europe, Asia, and South America. Zipeprol is not available in the United States or Canada and has been discontinued in Europe. Zipeprol is still available in some countries in Asia and South America. Zipeprol was demonstrated to have anticough effects in animal models, to be active as a blocker of histamine and cholinergic function, to be a potent local anesthetic and to possess bronchiospasmolytic actions. it had no remarkable cardiovascular or gastrointestinal actions in the rat or dog in comparison to codeine.