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Dyphylline/guaifenesin (By mouth)

Dyphylline (DYE-fi-lin), Guaifenesin (gwye-FEN-e-sin)

A combination drug that treats asthma, emphysema, and bronchitis. Dyphylline belongs to a class of drugs called bronchodilators. Guaifenesin is an expectorant that loosens mucus in your lungs.

Brand Name(s):

Difil-G 400, Jay-Phyl

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use this medicine if you have ever had an allergic reaction to guaifenesin, dyphylline, or a related drug such as aminophylline, theophylline, oxtriphylline, or theobromine.

How to Use This Medicine:

Capsule, Tablet, Liquid

  • Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
  • If this medicine upsets your stomach, you may want to take it after meals.
  • Measure the oral liquid medicine with a marked measuring spoon, oral syringe, or medicine cup.
  • Do not chew or crush the tablet or capsule. Swallow it whole with a full glass of water.

If a dose is missed:

  • Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

  • Store this medicine in a tight container at room temperature away from heat and light. Protect the tablets from moisture.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.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 probenecid (Benemid®).
  • Avoid drinking large amounts of caffeine (such as in coffee, tea, or some soft drinks) while you are using this medicine.

Warnings While Using This Medicine:

  • Make sure your doctor knows if you have thyroid problems, heart disease, high blood pressure, a stomach ulcer, or if you are pregnant or breast feeding.
  • Do not give this medicine to a baby or child under 6 years old unless your doctor tells you to.
  • Talk to your doctor before taking this medicine if you have asthma, emphysema, or a chronic cough from smoking.

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
  • Chest pain.
  • Fast or uneven heartbeat.
  • Severe headache.

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

  • Difficulty sleeping, irritability, or restlessness.
  • Nausea, vomiting, or stomach pain.
  • Dizziness.

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


Last Updated: 8/4/2014


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