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Guaifenesin/Phenylephrine, Oral

gwy-FEN-eh-sin fen-il-EF-rin

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KEY POINTS

  • This medicine is taken by mouth to relieve coughs due to common colds or other chest infections. Take it exactly as directed. Do not give a child under age 4 any cough and cold medicines unless specifically instructed to do so by your healthcare provider.
  • This medicine may cause unwanted side effects. Tell your healthcare provider if you have any side effects that are serious, continue, or get worse.
  • Tell all healthcare providers who treat you about all the prescription medicines, nonprescription medicines, supplements, natural remedies, and vitamins that you take.

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What are other names for this medicine?

Type of medicine: expectorant; decongestant

Generic and brand names: guaifenesin/phenylephrine, oral; Aldex G; Aquatab D; Deconex; Despec; Donatussin; Duomax; Ed Bron GP; Entex LQ; ExeFen PD; ExeTuss; Gentex LA; GFN 600/Phenylephrine 20; Gilphex TR; J-Max; Liquibid PD-R; Liquibid-D-R; Liquid PD; Liquibid D; Lusonex; Maxiphen; Mucus Relief Sinus; MyDex; Nariz; Nazarin; Norel EX; Pendex; PE/GUAI; Prolex D; Proset D; Reluri; Rescon GG; Sil-Tex; Simuc; Sitrex PD; Sudafed PE Nondrowsy; Triaminic Chest and Nasal Congestion; Zotex GPX (There may be other brand names for this medicine.)

What is this medicine used for?

This medicine is taken by mouth to relieve coughs and congestion due to common colds or other chest infections. Guaifenesin is an expectorant used to help bring up mucus from the lungs and thin secretions. Phenylephrine is a decongestant used to relieve a stuffy nose.

This medicine may be used to treat other conditions as determined by your healthcare provider.

What should my healthcare provider know before I take this medicine?

Before taking this medicine, tell your healthcare provider if you have ever had:

  • An allergic reaction to any medicine
  • A thyroid disorder
  • Diabetes
  • Glaucoma
  • Heart disease or irregular heartbeat
  • High blood pressure
  • Kidney or liver disease
  • Phenylketonuria (PKU). Some products contain phenylalanine.
  • Seizures
  • Trouble urinating or enlarged prostate

Do not take this medicine for long-term coughs caused by smoking, asthma, or COPD unless your healthcare provider approves. Do not take this medicine if you already cough up a lot of mucus.

Do not take this medicine if you have taken an MAO inhibitor within the last 14 days. Using these products together can cause very serious side effects.

Females of childbearing age: Tell your healthcare provider if you are pregnant or plan to become pregnant. It is not known whether this medicine will harm an unborn baby. Do not breast-feed while taking this medicine without your healthcare provider's approval.

How do I take it?

Check the label on the medicine for directions about your specific dose. Take this medicine exactly as your healthcare provider prescribes. If your healthcare provider has not given you specific instructions, follow the directions that come with the medicine package. Do not take more or take it longer than prescribed.

Do not use this medicine in children under age 4.

This medicine may come in different forms. If you have extended-release tablets, do not break, crush, or chew them. Swallow them whole. Ask your pharmacist if you have the extended-release tablets.

If you have the liquid form of this medicine, use the measuring spoon, cup, dropper, or oral syringe that comes with the medicine, or ask your pharmacist for one. Do not use a kitchen spoon because the dose may not be correct.

You may take this medicine with or without food. Taking it with meals may lessen the chance the drug will upset your stomach. Drink plenty of water with this medicine to help loosen the mucus.

Because the decongestant in this medicine can cause you to feel excited or active, take the last dose of the day before 6 PM to avoid problems sleeping.

What if I overdose?

If you or anyone else has intentionally taken too much of this medicine, call 911 or go to the emergency room right away. If you pass out, have seizures, weakness or confusion, or have trouble breathing, call 911. If you think that you or anyone else may have taken too much of this medicine, call the poison control center. Do this even if there are no signs of discomfort or poisoning. The poison control center number is 800-222-1222.

Symptoms of an acute overdose may include: nausea, vomiting, numbness, tingling, fast or irregular heartbeat, restlessness, nervousness, seizures.

What should I watch out for?

Do not give a child under age 4 any cough and cold medicines unless specifically instructed to do so by your healthcare provider. If your child is over the age of 4, ask your healthcare provider before giving cough and cold medicines.

Contact your healthcare provider if your symptoms have not improved within 7 days.

This medicine may make you dizzy or drowsy. Do not drive or operate machinery unless you are fully alert.

If you need emergency care, surgery, lab tests, or dental work, tell the healthcare provider or dentist you are taking this medicine.

What are the possible side effects?

Along with its needed effects, your medicine may cause some unwanted side effects. Some side effects may be very serious. Some side effects may go away as your body adjusts to the medicine. Tell your healthcare provider if you have any side effects that continue or get worse.

Life-threatening (Report these to your healthcare provider right away. If you cannot reach your healthcare provider right away, get emergency medical care or call 911 for help.): Allergic reaction (hives; itching; rash; trouble breathing; chest pain or tightness in your chest; swelling of your lips, tongue, and throat).

Serious (Report these to your healthcare provider right away.): Trouble urinating, chest pain, fast or pounding heartbeat.

Other: Dizziness, drowsiness, nausea, vomiting, stomach cramps, diarrhea, constipation, increased sweating, nervousness, restlessness, trouble sleeping, headache, mild rash.

What products might interact with this medicine?

When you take this medicine with other medicines, it can change the way this or any of the other medicines work. Nonprescription medicines, vitamins, natural remedies, and certain foods may also interact. Using these products together might cause harmful side effects. Talk to your healthcare provider if you are taking:

  • Antidepressants such as amitriptyline, desipramine (Norpramin), imipramine (Tofranil), and nortriptyline (Pamelor)
  • Beta blockers such as acebutolol (Sectral), atenolol (Tenormin), carvedilol (Coreg), labetalol (Trandate), metoprolol (Lopressor, Toprol), nadolol (Corgard), pindolol, and sotalol (Betapace, Sorine)
  • Digoxin (Lanoxin)
  • Doxepin (Silenor)
  • Ergot medicines such as bromocriptine (Cycloset, Parlodel), dihydroergotamine (D.H.E. 45, Migranal), ergotamine (Ergomar), and methylergonovine
  • Linezolid (Zyvox)
  • MAO inhibitors such as isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam, Zelapar), and tranylcypromine (Parnate) (Do not take a MAO inhibitor and this medicine within 14 days of each other.)
  • Medicines to treat breathing or lung problems such as aclidinium (Tudorza), albuterol (ProAir, Proventil, Ventolin), aminophylline, budesonide/formoterol (Symbicort), fluticasone/salmeterol (Advair), theophylline, tiotropium (Spiriva), umeclidinium (Incruse Ellipta), and umeclidinium/vilanterol (Anoro Ellipta)
  • Natural remedies such as ephedra, green tea, guarana, and yohimbe
  • Other allergy, cold, or cough medicines that contain a decongestant or cough suppressant
  • Procarbazine (Matulane)
  • Propranolol (Hemangeol, Inderal, InnoPran)
  • Stimulants such as dextroamphetamine (Dexedrine), methamphetamine (Desoxyn), and diet pills

If you are not sure if your medicines might interact, ask your pharmacist or healthcare provider. Keep a list of all your medicines with you. List all the prescription medicines, nonprescription medicines, supplements, natural remedies, and vitamins that you take. Be sure that you tell all healthcare providers who treat you about all the products you are taking.

How should I store this medicine?

Store this medicine at room temperature. Keep the container tightly closed. Protect it from heat, high humidity, and bright light.


This advisory includes selected information only and may not include all side effects of this medicine or interactions with other medicines. Ask your healthcare provider or pharmacist for more information or if you have any questions.

Ask your pharmacist for the best way to dispose of outdated medicine or medicine you have not used. Do not throw medicine in the trash.

Keep all medicines out of the reach of children.

Do not share medicines with other people.

Developed by RelayHealth.
Medication Advisor 2016.4 published by RelayHealth.
Last modified: 2016-10-17
Last reviewed: 2015-10-23
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Copyright © 2016 RelayHealth, a division of McKesson Technologies Inc. All rights reserved.
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