Robitussin (Guaifenesin) Recommended Dosing
For adults and children 12 years and older, the recommended dose of guaifenesin is 200-400 mg every 4 hours (not exceeding 6 doses in 24 hours), or 1200 mg every 12 hours for extended-release formulations. 1
Adult Dosing
- Immediate-release formulation: 10-20 mL (200-400 mg) every 4 hours, maximum 6 doses per 24 hours 1
- Extended-release formulation: 1200 mg (two 600 mg tablets) every 12 hours 2, 3
- The extended-release formulation provides bioequivalent steady-state exposure to the immediate-release formulation while reducing dosing frequency from every 4 hours to every 12 hours 2
Pediatric Dosing (Immediate-Release)
Children 6 to under 12 years:
- 5-10 mL (100-200 mg) every 4 hours, maximum 6 doses per 24 hours 1
Children 2 to under 6 years:
- 2.5-5 mL (50-100 mg) every 4 hours, maximum 6 doses per 24 hours 1
Children under 2 years:
- Consult a physician before use 1
Administration Considerations
- Food effects: Extended-release guaifenesin can be taken with or without food, though Tmax is delayed in the fed state compared to fasted state 2
- Multiple daily doses are required with immediate-release formulations to maintain 24-hour therapeutic effect 4
- The dosing range allows flexible dose titration to optimize plasma concentrations for symptom relief 4
Safety Profile
- Guaifenesin demonstrates a well-established and favorable safety profile in both adult and pediatric populations 4
- In a post-marketing surveillance study of 552 adults taking extended-release guaifenesin 1200 mg every 12 hours for 7 days, all adverse events were mild in severity with no serious adverse events or deaths 3
- The most common adverse events include gastrointestinal symptoms, nervous system effects, and psychiatric symptoms, all mild in nature 3