Dextromethorphan/guaifenesin/phenylephrine (By mouth)


Dextromethorphan (dex-troe-meth-OR-fan), Guaifenesin (gwye-FEN-e-sin), Phenylephrine (fen-il-EF-rin)

Relieves nasal congestion and cough due to respiratory tract infection.

Brand Name(s)

Actidom DMX, Ambi 10PEH/400GFN/20DM, Broncotron PED, Broncotron PED drops, Children's Mucinex Multi-Symptom Cold, Children's Robitussin Cough & Cold CF, Deconex DMX, Desgen DM, Desgen Pediatric Drops, Despec DM, Despec DM-G, Despec EDA, Exactuss, G-Supress DX, G-TRON PED

When This Medicine Should Not Be Used

How to Use This Medicine

Capsule, Tablet, Long Acting Tablet, Liquid

  • Your doctor will tell you how much medicine to use. Do not use more than directed.
  • It is best to take this medicine with food or milk.
  • Swallow the extended-release tablet whole. Do not crush, break, or chew it.

If a dose is missed:

  • You must use this medicine on a fixed schedule. Call your doctor or pharmacist if you miss a dose.

How to Store and Dispose of This Medicine

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you are using MAO inhibitors such as Eldepryl®, Marplan®, Nardil®, or Parnate®. Tell your doctor if you are using antiyhypertensives such as guanethidine, methyldopa, mecamylamine, or reserpine.
  • Make sure your doctor knows if you are using tricyclic antidepressants such as amitriptyline, doxepin, nortriptyline, Elavil®, or Sinequan®.
  • Make sure your doctor knows if you are using beta-blockers such as atenolol, labetalol, metoprolol, nadolol, propranolol, timolol, Inderal®, or Toprol®.
  • Make sure your doctor knows about all the other medicines that you are using.

Warnings While Using This Medicine

  • Make sure your doctor knows if you are breastfeeding.
  • Make sure your doctor knows if you have diabetes, enlarged prostate, glaucoma, heart disease, high blood pressure, or an overactive thyroid.

Possible Side Effects While Using This Medicine

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Anxiety, restlessness, or nervousness.
  • Decrease in how much or how often you urinate.
  • Depression.
  • Fast heartbeat.
  • Headache or dizziness.
  • Lightheadedness.
  • Pale lips or pale skin color.
  • Seizures.
  • Trouble breathing.

If you notice these less serious side effects, talk with your doctor:

  • Nausea.
  • Weakness in your body.
  • Tremor.

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Version Info

  • Last reviewed on 10/4/2017

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