Role of antitussive agents in the treatment of acute respiratory viral infections and influenza

Abstract

Viral upper respiratory infection  (VURI)-associated acute cough is the most common symptom worldwide among children and adults. It causes  serious  economic  and  social  problems  both  for individual  patients, patients’  families, and  the  health  care system as a whole. There is still no effective pharmacological agent  capable  of interfering  with all the main pathophysiological mechanisms involved in VURI-associated acute  cough. This circumstance partly explains  the increased prevalence of the prolonged course of acute  respiratory  infections, when the cough takes on the features  of subacute or post-infectious course. The pathophysiology of this symptom is being actively investigated to optimize  the treatment of cough. A viral infection  provokes an acute  cough  induced  by various irritative  stimuli, the  main one  being  secretions from the  respiratory  tract, which directly acts on reflexogenic areas  of the mucosa. Inflammatory mediators also play an important role, acting  on the peripheral sensory terminations of airways. Inflammatory mediators also induce post-infectious bronchial hyperreactivity, which is an important component of the pathogenesis of post-infectious cough. Recently, researchers are becoming increasingly interested in the  role of the  voluntary  or conscious  cough  component, which is implemented due  to the  cortical  response to afferent information  from the receptors of the upper respiratory tract.This hypothesis  explains the ineffectiveness of central antitussive agents  in patients with viral infection-associated dry cough  and  expands  the  possibilities  of peripheral antitussive agents represented by levodropropizine. In addition  to the  action  on nerve endings, the  agent  also affects  inflammatory  mediators, which enhances its ability to break the “vicious circle” of this symptom, prevents the development of post-infectious cough and promotes rehabilitation of the  bronchial  tree. The efficacy and safety of levodropropizine has been  demonstrated in clinical trials in both children and adults.