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Guaifenesin: Uses, Dosage and Side-Effects

Guaifenesin Medicine

Generic Name(s)— Guaifenesin

Brand Name(s)— Mucinex

Other Name(s)— Glyceryl guaiacolate

Drug Class— Expectorants

What is Guaifenesin?

Guaifenesin is an expectorant. In simple words, guaifenesin is a medication which is used to treat coughs and congestion caused by the common cold, bronchitis, and other breathing illnesses.

It works by loosening and thinning congestion in your chest and throat, making it easier to cough out through your mouth. It is consumed by mouth.

Important Information:

It is advised not to use this medicine if you are allergic to guaifenesin.

Use this medicine as prescribed by your doctor or exactly as directed on the label. Do not use this medicine in excessive quantity or for longer than recommended.

It is commonly found as part of over—the—counter combination medicine for cold and cough. You should read the labels or ask a doctor before using any other cold or cough medicine when taking guaifenesin.

Ask your doctor before giving it to a child as it is not recommended for children less than six years old. The misuse of cough and cold medicine can cause death in very young children.

You should also consume extra fluids to help loosen the congestion and lubricate your throat while you are taking this medicine. Be careful if you drive or do anything that requires you to be alert.

Before Taking This Medicine:

  • Ask your doctor if it is safe for you to use this medication if you have other medical conditions, including kidney disease, liver disease, or phenylketonuria (PKU)
  • It is not clear whether the medicine passes into breast milk or if it could harm a nursing baby. It is advisable to consult your doctor before using this medicine if you are breast—feeding
  • It is also not clear whether guaifenesin will harm an unborn baby. Ask your doctor before using this medicine if you are pregnant
  • Do not give this medicine to a child without doctor’s advice

Side-Effects of Guaifenesin:

Common side effects of guaifenesin include —

  • Dizziness
  • Drowsiness
  • Nausea
  • Rashes
  • Vomiting
  • Headaches
  • Decreased uric acid levels
  • Stomach pain

What Happens If I Miss A Dose?

If you are taking this medicine regularly, take the missed dose as soon as you remember. Skip the missed dose if it is almost the time for your next scheduled dose. Also, do not take extra medicine to make up the missed dose.

What Should I Avoid While Taking Guaifenesin?

The medicine may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Ask your doctor before taking any other cold or cough medicine because many combination medicines contain guaifenesin.

Taking certain products together can cause you to get too much of a certain drug.

What Other Drugs Will Affect Guaifenesin?

Other drugs may interact with guaifenesin, such as prescription and over—the—counter medicines, herbal products and vitamins. Tell your doctor about all the medicines you are currently using and medication you are going to start or stop.



  1. Guaifenesin; Medical and Pharmacy Editor: John P. Cunha, DO, FACOEP;
  2. Guaifenesin Side Effects; Medically reviewed by Last updated on Jul 4, 2019;
  3. Guaifenesin; Medically reviewed by Kaci Durbin, MD Last updated on Feb 7, 2019;

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