Maximum Daily Dose of Guaifenesin
The maximum daily dose of guaifenesin for adults is 2400 mg per day, typically administered as 400-800 mg every 6 hours. 1
Dosage Guidelines
Adult Dosing
- Standard dosing: 400-800 mg every 6 hours
- Maximum single dose: 800 mg
- Maximum daily dose: 2400 mg
- Extended-release formulation: 1200 mg every 12 hours 2
Pediatric Dosing
- Children (maximum): 15-20 mg/kg per day (1.0 g/day) 3
Formulation Options
Guaifenesin is available in multiple formulations:
- Immediate-release tablets (200-400 mg)
- Extended-release tablets (600-1200 mg)
- Liquid formulations
The extended-release formulation offers the convenience of twice-daily dosing compared to the immediate-release formulation which requires dosing every 4 hours to maintain therapeutic effect due to guaifenesin's short half-life 2.
Mechanism of Action
Guaifenesin is an expectorant that works by:
- Loosening mucus in the airways
- Making coughs more productive
- Improving mucociliary clearance
- Potentially inhibiting cough reflex sensitivity in patients with upper respiratory tract infections 4
Clinical Applications
Guaifenesin is primarily used for:
- Relief of chest congestion due to common cold
- Management of wet cough
- Stable chronic bronchitis (professional indication)
- Upper respiratory tract infections with mucus hypersecretion 5
Safety Considerations
Guaifenesin has a well-established safety profile when used at recommended doses:
- Generally well-tolerated in both adult and pediatric populations 5
- Common side effects include mild gastrointestinal disturbances
- Severe adverse events are rare when taken at recommended doses
However, caution is warranted as extremely high doses have been associated with:
- Central nervous system depression in overdose cases 6
- Potential for serious adverse effects when taken in quantities far exceeding the maximum recommended dose
Practical Administration Tips
- Take with food or milk if gastrointestinal complaints occur
- For extended-release formulations, tablets should be swallowed whole and not crushed or chewed
- The lowest effective dose should be used for the shortest duration consistent with treatment goals
- Multiple daily doses are needed to maintain 24-hour therapeutic effect with immediate-release formulations 5
Remember that guaifenesin is often found in combination products with other active ingredients (decongestants, antihistamines, cough suppressants), so care should be taken not to exceed the maximum daily dose when using multiple products containing guaifenesin.