title: Antitussive effect of the GABA-agonist baclofen.
abstract: BACKGROUND
  gamma-Aminobutyric acid (GABA) is a central inhibitory neurotransmitter that also exists in peripheral tissues, including the lung. The GABA-agonist baclofen has been shown, in animal studies, to inhibit cough via a central mechanism, but has not been investigated in humans (to our knowledge).
  
  
  OBJECTIVE
  To evaluate the antitussive effect of baclofen in normal human subjects.
  
  
  METHODS
  Randomized, double-blind, placebo-controlled study.
  
  
  METHODS
  Academic medical center.
  
  
  METHODS
  Twenty healthy, adult volunteers.
  
  
  METHODS
  Subjects underwent cough challenge with inhaled capsaicin before and after a 14-day course of baclofen, 10 mg three times daily, or placebo. Capsaicin cough threshold (C5) was defined as the concentration of inhaled capsaicin inducing five or more coughs.
  
  
  RESULTS
  Subjects receiving baclofen (n=10) demonstrated a significant elevation of capsaicin cough threshold compared with placebo subjects (n=10). Mean delta log C5 after treatment was 0.48+/-0.19 (SEM) for the baclofen group, and -0.06+/-0.12 for the placebo group (p=0.024). Six of 10 subjects receiving baclofen, but none of the 10 subjects receiving placebo, demonstrated a fourfold or greater increase in capsaicin cough threshold (p=0.0054).
  
  
  CONCLUSIONS
  The antitussive activity of low-dose, oral baclofen demonstrated in this study supports further investigation of this drug, or other GABA-agonists, for a potential therapeutic role in the treatment of pathologic cough.
authors.affiliation: Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
authors.forename: P V
authors.initials: PV
authors.lastname: Dicpinigaitis
authors.forename: J B
authors.initials: JB
authors.lastname: Dobkin
mesh_terms: D000328:Adult; D000996:Antitussive Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001418:Baclofen / Q000008:administration & dosage / Q000627:therapeutic use*; D002211:Capsaicin; D003371:Cough / Q000139:chemically induced / Q000188:drug therapy; D004311:Double-Blind Method; D005260:Female; D018755:GABA Agonists / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D008297:Male
chemical_list: D000996:Antitussive Agents; D018755:GABA Agonists; D001418:Baclofen; D002211:Capsaicin