What is the recommended dose and frequency for Mucinex (Guaifenesin) DM?

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Last updated: June 18, 2025 • View editorial policy

From the FDA Drug Label

DIRECTIONS Follow dosage below or use as directed by a physician. do not take more than 6 doses in any 24-hour period. age dose adults and children 12 years and over10 to 20 mL (2 to 4 teaspoonfuls) every 4 hours children 6 years to under 12 years5 to 10 mL (1 to 2 teaspoonfuls) every 4 hours children 2 to under 6 years of age2.5 to 5 mL (½ to 1 teaspoonful) every 4 hours children under 2 years of ageconsult a physician

The recommended dose and frequency for Mucinex (Guaifenesin) DM are:

  • Adults and children 12 years and over: 10 to 20 mL (2 to 4 teaspoonfuls) every 4 hours
  • Children 6 years to under 12 years: 5 to 10 mL (1 to 2 teaspoonfuls) every 4 hours
  • Children 2 to under 6 years of age: 2.5 to 5 mL (½ to 1 teaspoonful) every 4 hours
  • Children under 2 years of age: consult a physician 1

From the Research

The recommended dose of Mucinex DM (guaifenesin and dextromethorphan) for adults and children 12 years and older is one to two 600mg/30mg extended-release tablets every 12 hours, not exceeding 4 tablets in 24 hours. This dosing recommendation is based on the most recent and highest quality study available, which evaluated the pharmacokinetics and efficacy of extended-release guaifenesin formulations 2.

Key Considerations

  • Children under 12 should not take the adult formulation, but age-appropriate children's versions are available with different dosing.
  • The medication should be taken with a full glass of water to help loosen mucus, and tablets should be swallowed whole, not crushed or chewed, to maintain the extended-release properties.
  • Mucinex DM contains two active ingredients: guaifenesin, which helps thin and loosen mucus in the airways, and dextromethorphan, which suppresses cough.
  • The 12-hour dosing interval is designed to provide consistent symptom relief throughout the day.
  • If symptoms persist beyond 7 days, worsen, or are accompanied by fever, consult a healthcare provider as this may indicate a more serious condition requiring different treatment.

Supporting Evidence

  • A study published in 2013 demonstrated the bioequivalence of extended-release guaifenesin to immediate-release formulations, supporting the use of extended-release formulations for convenience and efficacy 2.
  • Another study published in 2017 highlighted the role of guaifenesin in the management of chronic bronchitis and upper respiratory tract infections, emphasizing its safety and efficacy profile 3.
  • However, a 2022 study on levofloxacin for tuberculosis treatment in children is not relevant to the dosing of Mucinex DM 4.
  • Other studies, such as those published in 2007 and 2015, provide additional context on the mechanisms and effects of guaifenesin, but do not alter the recommended dosing regimen 5, 6.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.