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Dextromethorphan, guaifenesin, and pseudoephedrine

Generic Name: dextromethorphan, guaifenesin, and pseudoephedrine (dex troe meth OR fan, gwye FEN e sin, soo doe e FED rin)
Brand Name: Altarussin CF, Capmist DM, Despec DM, Entre-Cough, Maxifed DMX, Robitussin Cold and Cough, Tusnel, ...show all 81 brand names

Medically reviewed on December 14, 2016.

What is dextromethorphan, guaifenesin, and pseudoephedrine?

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).

Dextromethorphan, guaifenesin, and pseudoephedrine is a combination medicine used to treat cough, stuffy nose, sinus congestion and chest congestion caused by allergies, the common cold, or the flu.

This medicine will not treat a cough that is caused by smoking, asthma, or emphysema.

Dextromethorphan, guaifenesin, and pseudoephedrine may also be used for purposes not listed in this medication guide.

Important Information

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

Before taking this medicine

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 dextromethorphan, guaifenesin, and pseudoephedrine if you have:

It is not known whether dextromethorphan, guaifenesin, and pseudoephedrine 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.

How should I take dextromethorphan, guaifenesin, and pseudoephedrine?

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 this medicine 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.

What happens if I miss a dose?

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.

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 dextromethorphan, guaifenesin, and pseudoephedrine?

This medicine 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. Dextromethorphan, guaifenesin, and pseudoephedrine 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.

Dextromethorphan, guaifenesin, and pseudoephedrine 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.

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 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.

See also: Side effects (in more detail)

What other drugs will affect dextromethorphan, guaifenesin, and pseudoephedrine?

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.

Further information

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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