Guaifenesin, a mucoactive
drug, acts by loosening mucus in the airways and making
coughs more productive. It is used for relief of wet
cough and chest congestion due to the
common cold, and remains the only legally marketed
expectorant in the US (per OTC Monograph). An ingredient in numerous over-the-counter (OTC)
cough/cold medications,
guaifenesin has a secondary indication for use in stable
chronic bronchitis (professional indication). Clinical pharmacology and patient studies support the clinical utility of
guaifenesin in respiratory conditions where mucus hypersecretion is prevalent: acute
upper respiratory tract infections (URTIs), stable
chronic bronchitis, and possibly
rhinosinusitis.
Guaifenesin has a well-established and favorable safety and tolerability profile in adult and pediatric populations. Its dosing range (200-400 mg 4-hourly, up to 6× daily) allows flexible dose titration to allow an increase of plasma concentrations. Multiple daily doses are needed to maintain 24-h
therapeutic effect with immediate-release formulations. Extended-release
guaifenesin tablet formulations are available, providing convenience with 12-hourly dosing and portability compared to liquids.
Guaifenesin is considered as a safe and effective
expectorant for the treatment of mucus-related symptoms in acute URTIs and stable
chronic bronchitis. Its clinical efficacy has been demonstrated most widely in chronic respiratory conditions, where excess mucus production and
cough are more stable symptoms. Progress is being made to establish clinical models and measures that are more appropriate for studying symptomatic relief with
guaifenesin in acute
respiratory infections. This will help generate the up-to-date and high-quality data needed to optimize
guaifenesin's effectiveness in established uses, and in new respiratory indications associated with mucus hypersecretion.