What is the maximum recommended dose of Guaifenesin (expectorant)?

Maximum Recommended Dose of Guaifenesin

The maximum recommended daily dose of guaifenesin for adults is 2.4 grams (2,400 mg) per day, typically administered as 1,200 mg every 12 hours for extended-release formulations or 400 mg every 4 hours for immediate-release formulations. 1, 2

Dosage Forms and Administration

• Guaifenesin is available in multiple formulations:

  • Immediate-release (IR) tablets/liquid: 200-400 mg every 4 hours, not to exceed 2,400 mg daily 1
  • Extended-release (ER) tablets: 600-1,200 mg every 12 hours, not to exceed 2,400 mg daily 2
  • Oral solution: Available in 200 mg/10 mL and 300 mg/15 mL concentrations 3

• The extended-release formulation offers more convenient dosing (twice daily) compared to immediate-release formulations that require dosing every 4 hours to maintain therapeutic effect 2

Safety Considerations

• Guaifenesin has a well-established and favorable safety profile in adult populations when used at recommended doses 1, 4

• Most common adverse effects are mild and include:

  • Gastrointestinal disturbances 4
  • Nervous system effects (e.g., dizziness, headache) 4
  • Skin reactions (uncommon) 4

• Caution: While rare, a case report documented central nervous system depression and asystole following a significant overdose of guaifenesin combined with other substances 5

Clinical Efficacy

• Guaifenesin acts as an expectorant by loosening mucus in the airways and making coughs more productive 1

• It is FDA-approved for relief of chest congestion and wet cough due to common cold and as an expectorant in stable chronic bronchitis 1

• Clinical studies have demonstrated efficacy in treating symptoms of upper respiratory tract infections, particularly when measured using validated patient-reported outcome instruments 6

Special Populations

• Pediatric dosing should be adjusted based on age and weight (not covered in the provided evidence)

• Safety data supports use in otherwise healthy adults with symptoms of cough, thickened mucus, and chest congestion associated with upper respiratory tract infections 4

Practical Considerations

• Extended-release formulations provide more consistent blood levels and reduce dosing frequency compared to immediate-release products 2

• Taking with food may delay peak concentration (Tmax) but does not significantly affect overall bioavailability of extended-release formulations 2