A new article published in Lung stated that in cough medicines, the taste and appearance are more important to the patient than the pharmacology of the active ingredient. In cough medicines, excipients – which generally act as vehicles and/or taste modulators, have more important and complex roles and they can also be the main active ingredient of the cough medicine, for example –menthol, glyceroland sugars. 

This article presented the results of a review that searched the United Kingdom electronic medicines compendium (emc), and found over 100 excipients in 60 different liquid formulations of over the counter cough medicines. The excipients were divided into functional groups: sweeteners, thickeners, flavors, colors, antimicrobials and buffers, and the incidence and function of the different excipients were discussed. 

The findings suggested that when considering the efficacy of a cough medicine, clinicians and pharmacists tend to think of the pharmacology of antitussives, such as dextromethorphan or expectorants like guaifenesin, and they rarely consider the role of excipients in the efficacy of the medicine. 

Source: Lung. 2020 Sep; 198(5): 727–734.doi: 10.1007/s00408-020-00390-x