What is dextromethorphan-guaifenesin?

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.

The combination of dextromethorphan and guaifenesin is used to treat cough and chest congestion caused by the common cold, infections, or allergies.

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

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


Do not use a cough or cold medicine if you have used an MAO inhibitor such as isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam), or tranylcypromine (Parnate) within the past 14 days. Serious, life-threatening side effects can occur if you take cough or cold medicine before the MAO inhibitor has cleared from your body.

Before taking dextromethorphan and guaifenesin, tell your doctor if you are allergic to any drugs, or if you have emphysema or chronic bronchitis. If you have any of these conditions, you may not be able to use this medication, or you may need a dosage adjustment or special tests during treatment.

FDA pregnancy category C. It is not known whether dextromethorphan and guaifenesin is harmful to an unborn baby. Before you take this medication, tell your doctor if you are pregnant or plan to become pregnant during treatment.

It is not known whether this medication passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

Artificially-sweetened liquid forms of cold medicine may contain phenylalanine. This would be important to know if you have phenylketonuria (PKU). Check the ingredients and warnings on the medication label if you are concerned about phenylalanine.

This medication can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert.

Avoid drinking alcohol. It can increase some of the side effects of this medication.

Avoid taking diet pills, caffeine pills, or other stimulants (such as ADHD medications) without your doctor’s advice. Taking a stimulant together with cough or cold medicine can increase your risk of unpleasant side effects.

Do not use any other over-the-counter cough or cold medication without first asking your doctor or pharmacist. Dextromethorphan and guaifenesin are contained in many medicines available over the counter. If you take certain products together you may accidentally take too much of one or more types of medicine. Read the label of any other medicine you are using to see if it contains dextromethorphan or guaifenesin.

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Seek emergency medical attention if you think you have used too much of this medicine.

Overdose symptoms may include feeling restless or nervous.

Since cough or cold medicine is usually taken only as 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. If it is almost time for your next dose, skip the missed dose and take the medicine at your next regularly scheduled time. Do not take extra medicine to make up the missed dose.

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Side effects

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

Stop using this medication and call your doctor at once if you have any of these serious side effects:

  • severe dizziness, anxiety, restless feeling, or nervousness;
  • confusion, hallucinations; or
  • slow, shallow breathing.

Less serious side effects may include:

  • dizziness;
  • headache;
  • skin rash or itching; or
  • nausea, vomiting, or 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. You may report side effects to FDA at 1-800-FDA-1088.

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Before taking this medication, tell your doctor if you are using any of the following drugs:

  • celecoxib (Celebrex);
  • cinacalcet (Sensipar);
  • darifenacin (Enablex);
  • imatinib (Gleevec);
  • quinidine (Quinaglute, Quinidex);
  • ranolazine (Ranexa);
  • ritonavir (Norvir);
  • sibutramine (Meridia);
  • terbinafine (Lamisil);
  • medicines to treat high blood pressure; or
  • an antidepressant such as amitriptyline (Elavil, Etrafon), bupropion (Wellbutrin, Zyban), fluoxetine (Prozac, Sarafem), fluvoxamine (Luvox), imipramine (Janimine, Tofranil), paroxetine (Paxil), sertraline (Zoloft), and others.

This list is not complete and there may be other drugs that can interact with dextromethorphan and guaifenesin. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

Other Names

Allfen-DM, Altarussin DM, Aquabid DM, Aquatab DM, Aquatab DM(obsolete), Atuss-12 DX, Benylin Expectorant, Bidex-A, Bidex-DM, Biotuss DM, Cheracol D Cough, Cheracol-D, Cofex-DM, Cough Formula-DM, Dex-Tuss DM, Diabetic Suppressant, Diabetic Tuss DM, Diabetic Tuss DM Maximum Strength, Double-Tussin DM, Drituss DM, DuraDEX, DuraDEX Forte, Duraganidin, Duratuss DM, Duratuss DM 12, Extuss LA, Fenesin DM, Fenex-DM, G Bid DM, G-Bid DM, GG-DM SR, Gani-Tuss-DM NR, Genatuss DM, Glycotuss-DM, Guai-Dex, Guaiasorb Cough Medicine, Guaifenesin DM, Guaifenesin DM SR, Guiacough DM, Guiat Clear DM, Guiatuss Clear, Guiatuss DM, Guiatussin-DM, HT Tuss DM, Halotussin DM, Halotussin DM Sugar Free, Humibid CS, Humibid DM Pediatric, Humigen DM, Iobid DM, Iofen-DM NF, Iophen DM NR, Kita La Tos, Kolephrin GG/DM, Lotussin DM, Mastussin DM, Mindal DM, Mintab DM, Monafed DM, Mucinex Children's Cough, Mucinex DM, Muco-Fen 800 DM, Muco-Fen DM, Mucobid DM, Mucus Relief DM, Mytussin DM, Naldecon DX Liquigel, Naldecon Senior DX, Nalspan Senior DX, Phanatuss, Phlemex, Q-Bid DM, Q-Tussin DM, Recofen D, Recofen Plus, Relacon LAX, Respa-DM, Rhinosyn-DMX, Ri-Tussin DM, Robafen DM, Robafen DM Clear, Robichem DM, Robitussin-DM, Robitussin-SF, Ru-Tuss 800 DM, S-Pack DM, Safetussin 30 DM, Scot-Tussin DM, Siltussin DM, Siltussin DM DAS Cough Formula, Simuc-DM, Su-Tuss DM, Sudal DM, T-Tussin DM, Tolu-Sed DM, Touro DM, Tuss-DM, Tusscidin DM, Tussi-Bid, Tussi-Organidin DM NR, Tussi-Organidin DM NR(obsolete), Tussi-Organidin DM-S NR, Tussi-Organidin DM-S NR(obsolete), Tussidin DM, Tussin DM, Vicks 44E, Vicks 44E Pediatric, Z-Cof LA, Z-Cof LAX, dextromethorphan-guaifenesin, guaifenesin-dextromethorphan, Allfen DM, Ambi 1000/55, Amibid DM, Anti-Tuss DM, Bidex-DMI, Children's Mucus Relief Cough, Coricidin HBP Chest Congestion & Cough Liqui-Gels, ExeFen-DM, Fenesin DM IR, GG/DM, Guaifen DM, Guaifen DM NR, Guaifenex DM, Guiadrine DM, Hydro-Tuss DM, Iophen DM, Maxi-Tuss DM, Mucinex Children's Cough Mini-Melts, Mucinex DM Max Strength, MucusRelief DM, Robitussin Cough & Congestion, Robitussin Cough & Congestion DM Max, Robitussin Cough Sugar-Free DM, Robitussin DM, Robitussin DM Infant Drops, Robitussin DM Sugar Free, Scot-Tussin Senior, Siltussin-DM DAS-NA, Siltussin-DM DAS-NA Maximum Strength, Tussin Cough, Tussi-Organidin DM-S NR (obsolete), and Zotex DMX

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Copyright 1996-2004 Cerner Multum, Inc. Version 2.05. Revision date 8/23/04

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