Generic name: guaifenesin [ gwye-FEN-e-sin ]
Drug class: Expectorants

Medically reviewed by Melisa Puckey, BPharm. Last updated on Feb 29, 2024.

What is Mucinex?

Mucinex is an expectorant. It helps loosen congestion in your chest and throat, making it easier to cough out through your mouth.

Mucinex is used to reduce chest congestion caused by the common cold, infections, or allergies.

Mucinex may also be used for purposes not listed in this medication guide.

Warnings

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 Mucinex if you are allergic to guaifenesin.

Ask a doctor or pharmacist if it is safe for you to use Mucinex if you have other medical conditions.

It is not known whether Mucinex 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 Mucinex to a child without medical advice.

How should I take Mucinex?

Use Mucinex 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 Mucinex 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.

Dosing information

Usual Adult Dose of Mucinex for Cough:

• Immediate release formulation: 200 to 400 mg orally every 4 hours as needed, not to exceed 2.4 g/day
• Sustained release formulation: 600 to 1200 mg orally every 12 hours, not to exceed 2.4 g/day

Usual Pediatric Dose of Mucinex for Cough:

Immediate release formulation:

• Less than 2 years: 12 mg/kg/day orally in 6 divided doses
• 2 to 5 years: 50 to 100 mg orally every 4 hours as needed, not to exceed 600 mg/day
• 6 to 11 years: 100 to 200 mg orally every 4 hours as needed, not to exceed 1.2 g/day
• 12 years or older: 200 to 400 mg orally every 4 hours as needed, not to exceed 2.4 g/day

Sustained release formulation:

• 2 to 5 years: 300 mg orally every 12 hours, not to exceed 600 mg/day
• 6 to 11 years: 600 mg orally every 12 hours, not to exceed 1.2 g/day
• 12 years or older: 600 to 1200 mg orally every 12 hours, not to exceed 2.4 g/day

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 to avoid

Mucinex 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 Mucinex. 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.

Mucinex side effects

Get emergency medical help if you have signs of an allergic reaction to Mucinex: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Common side effects of Mucinex may include:

• dizziness;
• headache;
• rash;
• nausea;
• vomiting;
• stomach upset.

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.

Related/similar drugs

What other drugs will affect Mucinex ?

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.

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Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Mucinex only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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