guaifenesin-phenylephrine (generic name)

MontePhen (brand name)

It is used to provide relief from cough and congestion
(gwye FEN e sin; fen il EF rin)
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What is this medicine?

GUAIFENESIN; PHENYLEPHRINE (gwye FEN e sin; fen il EF rin) is a decongestant, expectorant combination. It is used to provide relief from cough and congestion. This medicine will not treat an infection.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of the following conditions:
  • blood vessel disease
  • diabetes
  • fever
  • glaucoma
  • heart disease or heart rhythm problems
  • high blood pressure
  • other chronic disease
  • prostate trouble
  • taken an MAOI like Carbex, Eldepryl, Marplan, Nardil, or Parnate within the last 14 days
  • thyroid disease
  • an unusual or allergic reaction to guaifenesin, phenylephrine, other medicines, foods, dyes, or preservatives
  • pregnant or trying to get pregnant
  • breast-feeding

How should I use this medicine?

Take this medicine by mouth with a full glass of water. Follow the directions on the prescription label. Use a specially marked spoon or container to measure each dose. Ask your pharmacist if you do not have one. Household spoons are not accurate. Take your medicine at regular intervals. Do not take it more medicine than directed.

Talk to your pediatrician regarding the use of this medicine in children. While this drug may be prescribed for children as young as 2 years old for selected conditions, precautions do apply.

Patients over 65 years old may have a stronger reaction to this medicine and need smaller doses.

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

What may interact with this medicine?

Do not take this medicine with any of the following medications:
  • bromocriptine
  • ergot alkaloids like dihydroergotamine, ergonovine, ergotamine, methylergonovine
  • MAOIs like Carbex, Eldepryl, Marplan, Nardil, and Parnate
  • procarbazine
  • stimulant medicines for attention disorders, weight loss, or to stay awake

This medicine may also interact with the following medications:

  • indomethacin
  • mecamylamine
  • medicines for chest pain, heart disease, high blood pressure, or heart rhythm problems
  • medicines for depression, anxiety, or psychotic disturbances
  • methyldopa
  • other medicines for allergies or colds
  • reserpine
  • some medicines used during surgery

What should I watch for while using this medicine?

Tell your doctor or health care professional if your symptoms do not start to get better within 5 days or if they get worse. If you have trouble falling asleep at night, take the last dose of the day at least a few hours before bedtime.

Drink 6 to 8 glasses water daily while you are taking this medicine to help loosen mucus.

What side effects may I notice from receiving this medicine?

Side effects that you should report to your doctor or health care professional as soon as possible:
  • allergic reactions like skin rash, itching or hives, swelling of the face, lips, or tongue
  • breathing problems
  • confusion
  • fast, irregular heartbeat
  • hallucinations
  • high blood pressure
  • seizure
  • tremor
  • trouble passing urine

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):

  • anxiety, excitement, irritability, or nervousness
  • diarrhea
  • dizziness
  • headache
  • loss of appetite
  • stomach upset, nausea

Where should I keep my medicine?

Keep out of the reach of children.

Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F). Throw away any unused medicine after the expiration date.

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.

Last Updated: April 29, 2009
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