Muco-Fen 800 Side Effects
Generic name: guaifenesin
Medically reviewed by Drugs.com. Last updated on Jan 31, 2021.
Note: This document contains side effect information about guaifenesin. Some of the dosage forms listed on this page may not apply to the brand name Muco-Fen 800.
For the Consumer
Applies to guaifenesin: oral liquid, oral packet, oral solution, oral syrup, oral tablet, oral tablet extended release
Side effects requiring immediate medical attention
Along with its needed effects, guaifenesin (the active ingredient contained in Muco-Fen 800) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Side effects not requiring immediate medical attention
Some side effects of guaifenesin may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.
Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Less common or rare
For Healthcare Professionals
Applies to guaifenesin: compounding powder, oral capsule, oral capsule extended release, oral granule, oral liquid, oral solution, oral tablet, oral tablet extended release
Guaifenesin (the active ingredient contained in Muco-Fen 800) has been generally well tolerated.[Ref]
Gastrointestinal side effects have included stomach upset and vomiting with higher than recommended doses. Doses recommended for expectoration have rarely been associated with gastrointestinal upset.[Ref]
Nervous system side effects have occasionally included dizziness and headache.[Ref]
Dermatologic side effects have included rare reports of rash.[Ref]
Frequently asked questions
More about Muco-Fen 800 (guaifenesin)
Related treatment guides
1. Covington TR, Lawson LC, Young LL, eds. "Handbook of Nonprescription Drugs. 10th ed." Washington, DC: American Pharmaceutical Association (1993):
2. "Product Information. Robitussin (guaifenesin)." Wyeth-Ayerst Laboratories, Philadelphia, PA.
3. Manujendra R, Faltay B, Haller NA "Case report: anaphylactic reaction to guaifenesin." Hosp Pract 37 (2009): 60-3
Some side effects may not be reported. You may report them to the FDA.