Table 1

RCT-proven efficacy of antitussives by three different cough measurement methods in acute bronchitis

RCT-evidence for drug efficacySubjective clinical symptomsObjective cough recordingCough challengeRemarks
CodeineNo convincing evidence of efficacy
Dextromethorphan++++Well characterised in objective studies
PentoxyverineOnly animal studies via 3 clinical studies >50 years old
ButamirateNo placebo-controlled study published
Levodropropizine++6 short-term placebo or active comparator controlled studies n=174
Ambroxol+Many additional non-interventional studies
N-acetylcysteineChildren +
Adults −
Many studies for COPD, chronic cough, antioxidant properties
OxomemazineOnly observational studies
Menthol+Widely used. Vapour antitussive via TRPM8
HelicidineNo clinical evidence of efficacy in acute cough
DiphenhydramineBroad clinical use
  • COPD, chronic obstructive pulmonary disease; RCT, randomised controlled trial.