Prescription of mucoactive drugs for chronic obstructive pulmonary disease (COPD) is increasing. This development in clinical practice arises, at least in part, from a growing understanding of the important role that exacerbation frequency, systemic inflammation and oxidative stress play in the pathogenesis of respiratory disease. S-carboxymethylcysteine (carbocisteine) is the most frequently prescribed mucoactive agent for long-term COPD use in the UK. In addition to its mucoregulatory activity, carbocisteine exhibits free-radical scavenging and anti-inflammatory properties. These characteristics have stimulated interest in the potential that this and other mucoactive drugs may offer for modification of the disease processes present in COPD. This article reviews the pharmacology, in vivo and in vitro properties, and clinical trial evidence for carbocisteine in the context of guidelines for its use and the current understanding of the pathogenic processes that underlie COPD
