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Generic Name: guaifenesin (gwye-FEN-eh-sin)
Brand Names: Mucinex Sustained-Release Tablets

What is Mucinex:

Mucinex (guaifenesin) is used to relieve the symptoms of cough and mucus in the chest due to colds, flu, or hay fever. Mucinex may also be used for other conditions as determined by your doctor.

Mucinex is an expectorant. It works by thinning mucus (phlegm) in the lungs and making it less sticky and easier to cough up. This reduces chest congestion by making coughs more productive.

Important information

  • Do not use Mucinex if you are allergic to guaifenesin or any other ingredient found in Mucinex Sustained-Release tablets

Contact your doctor or health care provider right away if this applies to you.

Before using Mucinex.

Some medical conditions may interact with Mucinex. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

  • if you are pregnant, planning to become pregnant, or are breast-feeding
  • if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
  • if you have allergies to medicines, foods, or other substances
  • if you have a chronic cough that occurs with smoking, asthma, chronic bronchitis, or emphysema, or if your cough occurs with large amounts of mucus

Some medicine may interact with Mucinex. Tell your health care provider if you are taking any other medicines. However, no specific interactions with Mucinex are known at this time.

Ask your health care provider if Mucinex may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use Mucinex:

Use Mucinex Sustained-Release tablets as directed by your doctor. Check the label on the medicine for exact dosing instructions.

  • Take Mucinex by mouth with or without food.
  • Drinking extra fluids while you are taking Mucinex is recommended. Check with your doctor for instructions.
  • Swallow Mucinex Sustained-Release tablets whole. Do not break, crush, or chew a Mucinex tablet before swallowing.
  • If you miss a dose of Mucinex and you are taking it regularly, take it as soon as possible. If it is almost time for your next dose, skip the missed dose. Go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use Mucinex.

Important Mucinex safety information:

  • Pregnancy and breast-feeding: If you become pregnant while taking Mucinex, contact your doctor. You will need to discuss the benefits and risks of using Mucinex while you are pregnant. It is not known if guaifenesin is passed in to breast milk. If you are or will be breast-feeding while you are using Mucinex, check with your doctor. Discuss any possible risks to your baby.
  • If cough persists for more than 1 week or is accompanied by a fever, contact your health care provider. A persistent cough could be a sign of a serious condition.
  • Different brands of guaifenesin may have different dosing instructions for children. Follow the dosing instructions on the package labeling. If your doctor has given you instructions, follow those. If you are unsure of the dose to give a child, check with your doctor or pharmacist.

Mucinex Side effects:

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most common side effects persist or become bothersome:

Nausea; vomiting.

Seek medical attention right away if any of these severe side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue).

This is not a complete list of all Mucinex side effects that may occur. If you have questions about side effects, contact your health care provider. 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)

If overdosage is suspected:

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center:, or emergency room immediately.

Proper storage of Mucinex:

Store Mucinex at room temperature, between 59 and 86 degrees F (15 and 30 degrees C). Store away from heat, moisture, and light. Do not store in the bathroom. Keep Mucinex out of the reach of children and away from pets.

General information:

  • If you have any questions about Mucinex, please talk with your doctor, pharmacist, or other health care provider.
  • Mucinex are to be used only by the patient for whom it is prescribed. Do not share it with other people.
  • If your symptoms do not improve or if they become worse, check with your doctor.

This information is a summary only. It does not contain all information about Mucinex. If you have questions about the medicine you are taking or would like more information, check with your doctor, pharmacist, or other health care provider.

Issue Date: August 4, 2010, Database Edition