guaifenesin and dextromethorphan hydrobromide (Robitussin and Mucinex Formulas)

  • Pharmacy Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical and Pharmacy Editor: Charles Patrick Davis, MD, PhD
    Charles Patrick Davis, MD, PhD

    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

View the Finding Relief for Your Cough Slideshow

STORAGE: Store at room temperature between 15 C and 30 C (59 F and 86 F). Do not store liquid formulations in the refrigerator.

PRESCRIBED FOR: Guaifenesin and dextromethorphan temporarily relieve cough due to minor throat and bronchial irritations that are associated with cold. Guaifenesin/dextromethorphan also help loosen mucus and thin bronchial secretions.

DOSING:

Adults and children 12 years of age and older:

  • Robitussin DM and Robitussin DM Maximum Strength (liquid): Take 10 ml by mouth every 4 hours as needed. No more than 6 doses in 24 hours.
  • Mucinex Fast-Max DM: Take 20 ml by mouth every 4 hours. No more than 6 doses in 24 hours.
  • Robitussin DM Maximum Strength (capsules): Take 2 capsules by mouth every 4 hours as needed. No More than 12 capsules in 24 hours.
  • Mucinex DM: Take 1 or 2 tablets by mouth every 12 hours. No more than 4 tablets in 24 hours.
  • Mucinex DM Maximum Strength: Take 1 tablet by mouth every 12 hours. No more than 2 tablets in 24 hours.

Safe and effective use of guaifenesin and dextromethorphan is not established for children under 12 years of age.

DRUG INTERACTIONS: Guaifenesin/dextromethorphan should not be used with MAO inhibitors like phenelzine (Nardil), selegiline (Zelapar, Emsam, and Eldepryl), tranylcypromine (Parnate), procarbazine (Matulane), rasagiline (Azilect) and isocarboxazid (Marplan). Such combinations increase the risk of serious side effects. Guaifenesin/dextromethorphan should not be used within 14 days of using a MAO inhibitor.

PREGNANCY: There are no adequate studies done on guaifenesin and dextromethorphan determine safe and effective use in pregnant women.

NURSING MOTHERS: It is not known whether guaifenesin and dextromethorphan enter breast milk; therefore, it is best to be cautious before using it in nursing mothers.

SIDE EFFECTS: Side effects of guaifenesin and dextromethorphan are nausea, vomiting, constipation, drowsiness, and dizziness.

REFERENCES:

FDA Prescribing Information.

Medscape. dextromethorphan/guaifenesin (OTC).

Medically Reviewed by a Doctor on 7/25/2014

Quick GuideCold and Flu: Finding Relief for Your Cough

Cold and Flu: Finding Relief for Your Cough
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