Health Encyclopedia > Medications

codeine, guaifenesin, and phenylephrine

Pronunciation: KOE deen, gwye FEN e sin, FEN il EFF rin

Brand: Maxiphen CD, Maxiphen CDX

What is the most important information I should know about codeine, guaifenesin, and phenylephrine?

Multum emt

You should not use this medicine if you have severe liver disease, inflammatory bowel disease, severe constipation, a blockage in your stomach or intestines, severe colitis or toxic megacolon, if you have a colostomy or ileostomy, if you are unable to urinate, if you have been sick with diarrhea, if you recently drank large amounts of alcohol, or if you have a head injury or brain tumor.

Multum donot

Do not use this medicine if you have untreated or uncontrolled diseases such as glaucoma, asthma or COPD, high blood pressure, heart disease, coronary artery disease, or a thyroid disorder.

Multum donot

Do not use a cough or cold medicine if you have used an MAO inhibitor such as furazolidone (Furoxone), isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam, Zelapar), or tranylcypromine (Parnate) in the last 14 days. A dangerous drug interaction could occur, leading to serious side effects.

Multum habit

Codeine may be habit-forming and should be used only by the person for whom it was prescribed. Keep the medication in a secure place where others cannot get to it.

What is codeine, guaifenesin, and phenylephrine?

Codeine is a narcotic 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.

Phenylephrine is a decongestant that shrinks blood vessels in the nasal passages. Dilated blood vessels can cause nasal congestion (stuffy nose).

The combination of codeine, guaifenesin, and phenylephrine is used to treat stuffy nose, cough, sinus congestion, and chest congestion caused by allergies, the common cold, or the flu.

Multum smoking

Codeine, guaifenesin, and phenylephrine will not treat a cough that is caused by smoking, asthma, or emphysema.

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

What should I discuss with my healthcare provider before taking codeine, guaifenesin, and phenylephrine?

Multum donot

Do not use a cough or cold medicine if you have used an MAO inhibitor such as furazolidone (Furoxone), isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam, Zelapar), or tranylcypromine (Parnate) in the last 14 days. A dangerous drug interaction could occur, leading to serious side effects.

Multum emt

You should not use this medicine if you have severe liver disease, inflammatory bowel disease, severe constipation, a blockage in your stomach or intestines, severe colitis or toxic megacolon, if you have a colostomy or ileostomy, if you are unable to urinate, if you have been sick with diarrhea, if you recently drank large amounts of alcohol, or if you have a head injury or brain tumor.

Multum donot

Do not use this medicine if you have untreated or uncontrolled diseases such as glaucoma, asthma or COPD, high blood pressure, heart disease, coronary artery disease, or a thyroid disorder.

To make sure you can safely take this medicine, tell your doctor if you have any of these other conditions:

  • diabetes;
  • a heart rhythm disorder;
  • a history of alcoholism or drug addiction;
  • sleep apnea (breathing stops during sleep);
  • liver or kidney disease;
  • epilepsy or other seizure disorder;
  • cough with mucus, or cough caused by emphysema or chronic bronchitis;
  • gallbladder disease;
  • enlarged prostate or urination problems;
  • an adrenal gland tumor or disorder (such as Addison's disease);
  • if you are dehydrated; or
  • if you take potassium (Cytra, Epiklor, K-Lyte, K-Phos, Kaon, Klor-Con, Polycitra, Urocit-K).
Multum habit

Codeine may be habit forming and should be used only by the person it was prescribed for. Never share this medicine with another person, especially someone with a history of drug abuse or addiction.

Multum nopreg

FDA pregnancy category C. Codeine may cause addiction or withdrawal symptoms in a newborn if the mother takes the medication during pregnancy. Tell your doctor if you are pregnant or plan to become pregnant while using the medicine.

Multum nobrfeed

Codeine can pass into breast milk and may harm a nursing baby. The use of codeine by some nursing mothers may lead to life-threatening side effects in the baby. Decongestants may also slow breast milk production. Do not use this medicine without telling your doctor if you are breast-feeding a baby.

Older adults may be more likely to have side effects from this medicine.

How should I take codeine, guaifenesin, and phenylephrine?

Take exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label. This medicine is usually taken for only a short time until your symptoms clear up.

Multum donot

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.

Multum nochild

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.

Drink extra fluids to help loosen the congestion and lubricate your throat while you are taking this medication.

Multum emt

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.

Multum rt

Store at room temperature away from moisture and heat.

Keep track of the amount of medicine used from each new bottle. Codeine is a drug of abuse and you should be aware if anyone is using your medicine improperly or without a prescription.

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?

Multum emt

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of codeine can be fatal.

Overdose symptoms may include confusion, extreme weakness, pinpoint pupils, cold and clammy skin, weak pulse, slow breathing, fainting, or breathing that stops.

Overdose symptoms may also include severe forms of some of the side effects listed in this medication guide.

What should I avoid while taking codeine, guaifenesin, and phenylephrine?

Multum noalcohol

Do not drink alcohol while you are taking medicine that contains codeine. Dangerous side effects or death can occur when alcohol is combined with a narcotic medicine.

Multum donot

Ask a doctor or pharmacist before using any other cold, cough, allergy, or sleep medicine. Decongestants and cough suppressants 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 or cough suppressant.

Multum dizzy

This medicine may cause blurred vision or impair your thinking or reactions. Avoid driving or operating machinery until you know how codeine, guaifenesin, and phenylephrine will affect you.

What are the possible side effects of codeine, guaifenesin, and phenylephrine?

Multum emt

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

Multum donot

Stop using this medication and call your doctor at once if you have a serious side effect such as:

  • fast or uneven heart rate;
  • hallucinations;
  • confusion, severe dizziness or drowsiness, feeling like you might pass out;
  • tremor, seizure (convulsions);
  • pain or numbness in the arms or legs;
  • severe stomach cramps or constipation;
  • weak or shallow breathing;
  • urinating less than usual or not at all; or
  • dangerously high blood pressure (severe headache, blurred vision, buzzing in your ears, confusion, anxiety, chest pain, shortness of breath, uneven heartbeats, seizure).

Less serious side effects may include:

  • dizziness, drowsiness;
  • constipation;
  • blurred vision;
  • feeling nervous, restless, or anxious; or
  • sleep problems (insomnia).

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.

What other drugs will affect codeine, guaifenesin, and phenylephrine?

Multum dizzy

Before using this medication, tell your doctor if you regularly use other medicines that can make you sleepy or slow your breathing (such as cold or allergy medicine, narcotic pain medications, sedatives, tranquilizers, sleeping pills, muscle relaxers, and medicine for seizures, depression, or anxiety).

Tell your doctor about all other medicines you use, especially:

  • alvimopan (Entereg);
  • naloxone (Narcan, Suboxone);
  • tramadol (Ultram, Ultracet);
  • an antidepressant such as amitriptyline (Elavil, Vanatrip, Limbitrol), bupropion (Wellbutrin), citalopram (Celexa), clomipramine (Anafranil), desipramine (Norpramin), doxepin (Sinequan, Silenor), duloxetine (Cymbalta), escitalopram (Lexapro), fluoxetine (Prozac, Rapiflux, Sarafem, Selfemra, Symbyax), fluvoxamine (Luvox), milnacipran (Savella), nortriptyline (Pamelor), paroxetine (Paxil, Pexeva), sertraline (Zoloft), trazodone (Desyrel, Oleptro), venlafaxine (Effexor), or vilazodone (Viibryd); or
  • bowel cleansing preparations (Half Lytely, Fleet Prep Kit, Evac-Q-Kwik, GoLytely, Supraprep, and others).

This list is not complete and other drugs may interact with codeine, guaifenesin, and phenylephrine. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.

Where can I get more information?

Your pharmacist can provide more information about codeine, guaifenesin, and phenylephrine.


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.

Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

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