Dextromethorphan is a cough suppressant. It affects the signals in the brain that trigger cough reflex.

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

Pseudoephedrine is a decongestant that shrinks blood vessels in the nasal passages. Dilated blood vessels can cause nasal congestion (stuffy nose).

Poly-Vent DM is a combination medicine used to treat cough, stuffy nose, sinus congestion and chest congestion caused by allergies, the common cold, or the flu.

Poly-Vent DM will not treat a cough that is caused by smoking, asthma, or emphysema.

Poly-Vent DM may also be used for purposes not listed in this medication guide.

Do not use Poly-Vent DM if you have used an MAO inhibitor in the past 14 days, such as isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, or tranylcypromine.

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 and cold medicine is usually taken only for a short time until your symptoms clear up.

Do not give this medication to a child younger than 4 years old. Always ask a doctor before giving a cough or cold medicine to a child. Death can occur from the misuse of cough and cold medicines in very young children.

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

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.

If you need surgery or medical tests, tell the surgeon or doctor ahead of time if you have taken Poly-Vent DM within the past few days.

Do not take for longer than 7 days in a row. Talk with your doctor if your symptoms do not improve after 7 days of treatment, or if you have a fever with a headache or skin rash.

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 pseudoephedrine.

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 it is safe for you to take Poly-Vent DM if you have:

• high blood pressure or coronary artery disease;

• diabetes;

• glaucoma;

• epilepsy or other seizure disorder;

• enlarged prostate or urination problems;

• pheochromocytoma (an adrenal gland tumor); or

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

It is not known whether Poly-Vent DM will harm an unborn baby. Ask a doctor before using this medicine if you are pregnant.

This medicine may pass into breast milk and may harm a nursing baby. Decongestants may also slow breast milk production. Ask a doctor before using this medicine if you are breast-feeding a baby.

Artificially sweetened cold medicine may contain phenylalanine. If you have phenylketonuria (PKU), check the medication label to see if the product contains phenylalanine.

Since this 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.

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

Poly-Vent DM may cause blurred vision or impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert and able to see clearly.

Drinking alcohol can increase certain side effects of this medicine.

Ask a doctor or pharmacist before using any other cold, cough, or allergy medicine. Poly-Vent DM are contained in many combination medicines. Taking certain products together can cause you to get too much of a certain drug. Check the label to see if a medicine contains a decongestant, expectorant, or cough suppressant.

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

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

• fast or uneven heart rate;

• severe dizziness or anxiety, feeling like you might pass out;

• severe headache;

• mood changes;

• fever; or

• dangerously high blood pressure (severe headache, blurred vision, buzzing in your ears, anxiety, chest pain, uneven heartbeats, seizure).

Common side effects of Poly-Vent DM may include:

• diarrhea;

• 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.

Ask a doctor or pharmacist before using this medicine if you are also using any other drugs, including prescription and over-the-counter medicines, vitamins, and herbal products. Some medicines can cause unwanted or dangerous effects when used together. Not all possible interactions are listed in this medication guide.

Taking this medicine with other drugs that make you sleepy or slow your breathing can worsen these effects. Ask your doctor before taking this medicine with a sleeping pill, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.