Guaifenesin Dosing Frequency
For adults and children 12 years and older, take guaifenesin every 4 hours, not exceeding 6 doses in 24 hours. 1
Dosing by Age Group
Adults and Children ≥12 Years
- Immediate-release formulation: 200-400 mg every 4 hours (maximum 6 doses/24 hours) 1, 2
- Extended-release formulation: 1200 mg (two 600 mg tablets) every 12 hours 3, 4
Children 6 to <12 Years
- Immediate-release: 100-200 mg (1-2 teaspoonfuls of liquid) every 4 hours 1
- Maximum 6 doses in 24 hours 1
Children 2 to <6 Years
Children <2 Years
- Consult a physician before use 1
Formulation Considerations
Extended-release guaifenesin offers the advantage of 12-hour dosing compared to 4-hour dosing required for immediate-release formulations. 2, 3 The extended-release bi-layer tablet formulation maintains therapeutic plasma concentrations over 12 hours and is bioequivalent to corresponding immediate-release doses given every 4 hours 3. At steady state, 1200 mg extended-release every 12 hours provides equivalent exposure to 400 mg immediate-release every 4 hours 3.
Important Dosing Caveats
- Multiple daily doses are necessary to maintain 24-hour therapeutic effect with immediate-release formulations due to guaifenesin's short half-life 2
- Extended-release formulations can be taken with or without food, though Tmax is delayed in the fed state 3
- The 4-hour dosing interval for immediate-release products allows flexible dose titration (200-400 mg range) to optimize therapeutic plasma concentrations 2
- Treatment duration in clinical studies typically ranged from 7 days for acute upper respiratory tract infections 4, 5