Geri-Tussin (Guaifenesin) Dosing
For adults, the standard immediate-release guaifenesin dose is 200-400 mg orally every 4 hours (up to 6 times daily), while extended-release formulations are dosed at 600-1200 mg every 12 hours. 1, 2
Standard Dosing Regimens
Immediate-Release Formulations
- Adults: 200-400 mg orally every 4 hours, maximum 6 doses per 24 hours (2400 mg/day) 2
- Pediatric dosing (based on standard guaifenesin formulations): Each 5 mL typically contains 100 mg guaifenesin 1
- The flexible dosing range allows titration to increase plasma concentrations as needed for symptom control 2
Extended-Release Formulations
- Adults: 600-1200 mg orally every 12 hours 3, 2
- Extended-release tablets provide convenience with twice-daily dosing compared to immediate-release formulations requiring dosing every 4 hours 3, 2
- The 1200 mg extended-release dose demonstrates bioequivalence to 400 mg immediate-release dosed every 4 hours at steady state 3
Administration Considerations
Food Effects
- Extended-release guaifenesin can be taken with or without food, though food delays time to maximum concentration (Tmax) without affecting overall exposure (AUC) 3
- Immediate-release formulations can be taken without regard to meals 2
Formulation Options
- Available as tablets (immediate and extended-release), capsules, and oral solutions 1, 2
- Oral solution concentration: 100 mg per 5 mL or 300 mg per 15 mL 1
- Extended-release formulations offer portability advantages over liquid formulations 2
Clinical Context
Multiple daily doses are required with immediate-release formulations to maintain 24-hour therapeutic effect due to guaifenesin's short half-life 3, 2. The drug acts as an expectorant by loosening mucus in airways and making coughs more productive, with primary indications for wet cough and chest congestion from upper respiratory tract infections 2.