Medically reviewed on December 14, 2016
What is guaifenesin?
Guaifenesin is an expectorant. It helps loosen congestion in your chest and throat, making it easier to cough out through your mouth.
Guaifenesin may also be used for purposes not listed in this medication guide.
Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.
Before taking this medicine
You should not use this medicine if you are allergic to guaifenesin.
Ask a doctor or pharmacist if it is safe for you to use this medicine if you have other medical conditions.
It is not known whether guaifenesin will harm an unborn baby. Ask a doctor before using this medicine if you are pregnant.
It is not known whether guaifenesin passes into breast milk or if it could harm a nursing baby. Ask a doctor before using this medicine if you are breast-feeding a baby.
Do not give this medicine to a child without medical advice.
How should I take guaifenesin?
Use exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended. Cough medicine is usually taken only for a short time until your symptoms clear up.
Take guaifenesin with food if it upsets your stomach.
Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.
Drink extra fluids to help loosen the congestion and lubricate your throat while you are taking this medication.
Store at room temperature away from moisture, heat, and light.
What happens if I miss a dose?
Since cough or cold medicine is taken when needed, you may not be on a dosing schedule. If you are taking the medication regularly, take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What should I avoid while taking guaifenesin?
This medication may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.
Ask a doctor or pharmacist before using any other cold, or cough medicine. Many combination medicines contain guaifenesin. Taking certain products together can cause you to get too much of a certain drug. Check the label to see if a medicine contains an expectorant.
Guaifenesin side effects
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Common side effects may include:
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
What other drugs will affect guaifenesin ?
Other drugs may interact with guaifenesin, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
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- Drug class: expectorants