Dextromethorphan is a cough suppressant that affects signals in the brain that trigger cough reflex. Guaifenesin is an expectorant that loosens congestion in your chest and throat. Phenylephrine is a decongestant that shrinks blood vessels in the nasal passages.

Mucinex Fast-Max Severe Congestion & Cough is a combination medicine used to treat cough, stuffy nose, and chest congestion caused by allergies, the common cold, or the flu.

Mucinex Fast-Max Severe Congestion & Cough will not treat a cough that is caused by smoking, asthma, or emphysema.

There are many brands and forms of this medicine available. Not all brands are listed on this leaflet.

Mucinex Fast-Max Severe Congestion & Cough may also be used for purposes not listed in this medication guide.

Do not use this medicine if you have taken an MAO inhibitor in the past 14 days, such as isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine.

Use exactly as directed on the label, or as prescribed by your doctor. Cold or cough medicine is only for short-term use until your symptoms clear up.

Always follow directions on the medicine label about giving cough or cold medicine to a child. Do not use the medicine only to make a child sleepy. Death can occur from the misuse of cough or cold medicines in very young children.

Do not crush, chew, or break an extended-release tablet. Swallow it whole.

Measure liquid medicine carefully. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

Drink extra fluids to help loosen the congestion and lubricate your throat while you are taking this medication.

Call your doctor if your symptoms do not improve after 7 days, or if you have a fever, rash, or headaches.

If you need surgery or medical tests, tell the surgeon or doctor ahead of time if you have taken this medicine within the past few days.

Store at room temperature away from moisture and heat. Do not allow liquid medicine to freeze.

You should not use this medicine if you are allergic to dextromethorphan, guaifenesin, or phenylephrine.

Do not use this medicine if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine.

Ask a doctor or pharmacist if this medicine is safe to use if you have:

• heart disease, high blood pressure;

• diabetes;

• a thyroid disorder;

• urination problems;

• glaucoma;

• epilepsy or other seizure disorder;

• pheochromocytoma (an adrenal gland tumor); or

• cough with mucus, or cough caused by emphysema or chronic bronchitis.

This medicine may contain phenylalanine. Check the medication label if you have phenylketonuria (PKU).

Ask a doctor before using this medicine if you are pregnant or breast-feeding.

Since cough or cold medicine is used when needed, you may not be on a dosing schedule. Skip any missed dose if it's almost time for your next dose. Do not use two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Avoid driving or hazardous activity until you know how this medicine will affect you. Your reactions could be impaired.

Drinking alcohol can increase certain side effects of this medicine.

Ask a doctor or pharmacist before using other cough or cold medicines that may contain similar ingredients.

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

This medicine may cause serious side effects. Stop using this medicine and call your doctor at once if you have:

• little or no urination;

• fast or slow heartbeats;

• confusion, dizziness, feeling unsteady;

• nervousness, sleep problems (insomnia);

• severe nausea or vomiting;

• severe headache, blurred vision, pounding in your neck or ears;

• slow breathing; or

• unusual changes in mood or behavior.

Common side effects of Mucinex Fast-Max Severe Congestion & Cough may include:

• diarrhea, constipation;

• dizziness, drowsiness;

• sleep problems (insomnia); or

• feeling nervous, restless, or irritable.

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.

Avoid using Mucinex Fast-Max Severe Congestion & Cough with other drugs that cause drowsiness or slow your breathing (such as opioid medicine, a muscle relaxer, or medicine for anxiety or seizures). Ask a doctor or pharmacist before using any other medication, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed in this medication guide.