Mucinex (Guaifenesin) Dosing Recommendations
For adults and children ≥12 years, the FDA-approved dose of immediate-release guaifenesin is 200-400 mg every 4 hours (maximum 2400 mg/24 hours), while extended-release formulations are dosed at 600-1200 mg every 12 hours. 1
Adult Dosing
Immediate-Release Formulation
- Dose: 10-20 mL (200-400 mg) every 4 hours 1
- Maximum: Do not exceed 6 doses in 24 hours 1
- Flexibility: The dosing range allows titration to achieve adequate plasma concentrations based on symptom severity 2
Extended-Release Formulation
- Dose: 600-1200 mg every 12 hours 3
- Bioequivalence: The 1200 mg ER dose every 12 hours provides steady-state exposure equivalent to 400 mg IR every 4 hours 3
- Food effect: Can be taken with or without food, though Tmax is delayed in the fed state without affecting overall bioavailability 3
Pediatric Dosing
Children 6 to <12 Years
Children 2 to <6 Years
Children <2 Years
- Consult a physician before administering 1
- Dosing in this age group has not been adequately established in FDA labeling 1
Clinical Context
Guaifenesin is an expectorant that works by loosening mucus in airways and making coughs more productive. 2 It is indicated for relief of wet cough and chest congestion due to common cold and has a secondary indication for stable chronic bronchitis 2. The drug increases hydration and decreases viscosity of mucus, leading to improved clearance of secretions 4.
Safety Profile
- Guaifenesin has a well-established and favorable safety profile in both adult and pediatric populations 2
- In a post-marketing surveillance study of 552 adults, only 28 patients experienced adverse events, all mild in severity, with no serious adverse events or deaths 5
- Common adverse effects when they occur include gastrointestinal symptoms, nervous system effects, and mild psychiatric symptoms 5
Formulation Considerations
- Extended-release tablets provide convenience with 12-hour dosing and improved portability compared to liquid formulations 2
- Multiple daily doses of immediate-release formulations are required to maintain 24-hour therapeutic effect 2
Important Caveats
The evidence for guaifenesin's clinical efficacy is limited. A Cochrane review found no good evidence for or against the effectiveness of OTC cough medicines, including expectorants, in acute cough 6. However, guaifenesin remains the only legally marketed expectorant in the United States per OTC Monograph 2, and clinical efficacy has been demonstrated most widely in chronic respiratory conditions where mucus production is a stable symptom 2.