Centrally acting antitussive agents

In Japan, 3,17-dimethylmorphinan phosphate (Dimemorfan) has been marketed as a centrally acting antitussive agent,(54) and the related (+)-3-ethyl-17-methyl analog is reported in the patent literature to have analgesic and antitussive properties/543 ... 

It was recently recognized that opioid receptor agonists have antitussive effects [31]. Morphine (Fig. 7) is a potent p opioid receptor agonist that exhibits marked antitussive effect, and it has been used for the treatment of severe coughs. Codeine (Fig. 7) is one of the most reliable centrally acting antitussive agents its antitussive... 

Expectorants and antitussive agents may be broadly classified into the following three categories (/) Sedative Expectorants (n) Stimulant (Irritant) Expectorants iii) Centrally Acting Antitussive Agents. 

Name two drugs that act as centrally acting antitussive agents and are analogues of morphine. Discuss the synthesis of one such compound. 

Current antitussives are broadly divided according to their site of action as either central or peripheral, although many act to some extent at both locations. Centrally acting antitussives act within the central nervous system (CNS) to suppress central cough pathways and comprise the majority of currently used drugs. However, opioids, which are gold standard antitussive agents, suffer from numerous... 

It is a potent antitussive agent. It usually acts by inhibiting transmission of impulses of the cough reflex in the vagal nuclei of the medulla and predominantly depresses polysynaptic spinal reflexes. It is regarded as a cough suppressant acting both centrally and peripherally... 

Dextromethorphan is the methylated dextro-isomer of levorphanol. Unlike the L-isomer, it has no analgesic properties. Dextromethorphan acts on the central nervous system (CNS) to elevate the cough threshold. It retains only the antitussive activity of other morphine derivatives. Administration of dextromethorphan may be associated with histamine release. Dextromethorphan is often present in multisymptom products with a combination of ingredients. Toxic effects of concurrent agents such as antihistamines, decongestants, analgesics, and/or alcohol may be exhibited. 

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