What is the recommended dosing of Mucinex (guaifenesin) for adults, children ≥12 years, children 4–11 years, and what adjustments are needed for renal impairment, pregnancy, or nursing?

Mucinex (Guaifenesin) Dosing

For adults and children ≥12 years, the standard dose is 600-1200 mg every 12 hours for extended-release formulations (maximum 2400 mg/day), or 200-400 mg every 4 hours for immediate-release formulations (maximum 2400 mg/day). 1, 2

Adult and Adolescent Dosing (≥12 years)

Extended-Release Formulation:

• 600-1200 mg orally every 12 hours 1, 3
• Maximum daily dose: 2400 mg/day 2
• Can be taken with or without food, though Tmax is delayed in fed state 1
• Provides equivalent steady-state exposure to immediate-release formulations dosed every 4 hours 1

Immediate-Release Formulation:

• 200-400 mg orally every 4 hours 2
• Maximum 6 doses per 24 hours (2400 mg/day) 2
• Requires more frequent dosing due to short half-life 1

Pediatric Dosing (Ages 4-11 years)

Extended-Release Formulation:

• 600 mg orally every 12 hours 4
• This provides similar systemic exposure to the lower adolescent dose 4

Immediate-Release Formulation:

• 100-200 mg orally every 4 hours 4
• Maximum 6 doses per 24 hours 2

Pediatric Dosing (Ages 2-3 years)

• 50-100 mg orally every 4 hours 4
• Maximum 6 doses per 24 hours 2
• Pharmacokinetic data support age-based dosing in this population 4

Special Populations

Renal Impairment:

• No specific dose adjustments are documented in the available evidence for guaifenesin 1, 2, 4
• Guaifenesin is primarily metabolized hepatically and renally excreted, but no formal renal dosing guidelines exist in the literature reviewed

Pregnancy:

• No specific contraindications or dose adjustments are provided in the available evidence 2, 3
• Guaifenesin has been used in pregnancy, though formal safety data are limited

Nursing:

• No specific contraindications or dose adjustments are documented 2, 3

Administration Considerations

• Extended-release tablets should be swallowed whole, not crushed or chewed 1
• Food delays absorption but does not significantly affect total exposure 1
• Liquid formulations are available for patients unable to swallow tablets 2
• Multiple daily doses maintain 24-hour therapeutic effect with immediate-release formulations 2

Safety Profile

• Well-tolerated with mild gastrointestinal and nervous system effects being most common 3
• 29 treatment-emergent adverse events in 28/552 patients (5.1%), all mild severity 3
• No serious adverse events or deaths reported in post-marketing surveillance 3