Guaifenesin and phenylephrine

Generic name: guaifenesin and phenylephrine [ gwye-FEN-e-sin-and-FEN-il-EFF-rin ]
Brand names: Aldex G, Aquatab D, Deconex, Deconex IR, Donatussin Drops, ... show all 115 brands D-Phen 1000, Duravent PE, Gilphex TR, Liquibid-PD, MucaphEd, Nariz, Prolex D, Sudafed PE Non-Drying Sinus, Supress-PE, Triaminic Chest & Nasal Congestion, Xpect-PE, Sinupan, Deconsal Pediatric, Efasin, Amidal, Chemdal, Quindal, Endal, Liquibid-D, Rescon-GG, SINUvent PE, Entex LA, Entex (obsolete formulation), Crantex, Crantex LA Capsules, Amitex LA, Entex ER, Duraphen II, Crantex ER, Liquibid-D 1200, Phenavent LA, Phenavent D, Sina-12X, Deconsal II, Guaifed Caps, Guaifed PD, Phenavent, Tussbid, Phenavent PED, Nescon-PD, Pendex, Prolex PD, Aldex, Nasex, Crantex LA Tablets, Duratuss, Duratuss GP, Lusonex, Sitrex, Guaiphen-PD, Wellbid-D, Wellbid-D 1200, Despec, Xedec, Nasex-G, Gentex LA, Guaiphen-D 600, Guaiphen-D 1200, Simuc, Zotex GPX, Duomax, Guaifen PE, Norel EX, Nexphen PD, Respa-PE, Reluri, Duraphen 1000, Dynex LA, Sudex, Extendryl G, Maxiphen, Ambi 40/1000, MontePhen, Xedec II, Simuc-GP, Triaminic Chest and Nasal Congestion, Duratuss PE, Sitrex PD, Refenesen PE, Mydex, Medent-PE, Genexa LA, Nazarin, J-Max, Mucus Relief Sinus, Robitussin Head and Chest Congestion, Visonex, Zyrphen, PE-Guai, Guiadex PD, D-Tab, ExeTuss, ExeTuss-GP, Mucinex Children's Cold, Quintex, Guiatex PE, Fenesin PE IR, Medent-PEI, Liquibid PD-R, Liquibid D-R, Zoden Drops, Entex LQ, Tussi-Pres PE, Lusair, Reese Onetab Congestion and Cough, ED Bron GP, Relcof IR, Giltuss Sinus and Congestion, Mucinex Children's Stuffy Nose and Chest Congestion, Maxi-Tuss PE Jr
Dosage forms: oral drops (20 mg-1.5 mg/mL), oral liquid (200 mg-7.5 mg/5 mL; 50 mg-2.5 mg/5 mL; 50 mg-2.5 mg/mL), oral tablet (200 mg-5 mg; 380 mg-10 mg; 385 mg-10 mg; 388 mg-10 mg; 395 mg-10 mg; 400 mg-10 mg), oral tablet, extended release (1000 mg-30 mg; 1100 mg-30 mg; 1200 mg-25 mg; 1200 mg-30 mg; 315 mg-20 mg; 600 mg-20 mg; 835 mg-25 mg; 835 mg-30 mg)
Drug class: Upper respiratory combinations

Medically reviewed by Drugs.com on Jan 16, 2023. Written by Cerner Multum.

What is guaifenesin and phenylephrine?

There are many brands and forms of guaifenesin and phenylephrine available and not all brands are listed on this leaflet.

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).

Guaifenesin and phenylephrine is a combination medicine used to treat stuffy nose and sinus congestion, and to reduce chest congestion caused by the common cold or flu.

Guaifenesin and phenylephrine may also be used for purposes not listed in this medication guide.

Warnings

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.

Before taking this medicine

You should not use guaifenesin and phenylephrine if you are allergic to it.

Do not use guaifenesin and phenylephrine if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine.

Ask a doctor or pharmacist if it is safe for you to take this medication if you have:

• high blood pressure, heart disease, coronary artery disease;

• diabetes;

• circulation problems;

• glaucoma;

• overactive thyroid; or

• enlarged prostate or problems with urination.

It is not known if this medication may be harmful to an unborn baby. Do not use guaifenesin and phenylephrine without medical advice if you are pregnant.

Guaifenesin and phenylephrine may pass into breast milk and may harm a nursing baby. Decongestants may also slow breast milk production. Do not use this medicine without medical advice if you are breast-feeding a baby.

Artificially sweetened liquid medicine may contain phenylalanine. Check the medication label if you have phenylketonuria (PKU).

How should I take guaifenesin and phenylephrine?

Use exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended. Cough or cold medicine is usually taken only for a short time until your symptoms clear up.

Do not give this medication to a child younger than 4 years old. Always ask a doctor before giving cough or cold medicine to a child. Death can occur from the misuse of cough or cold medicine in very young children.

Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

Do not crush, chew, break, or open an extended-release tablet or capsule. Swallow it whole.

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

Call your doctor if your symptoms do not improve after 7 days of treatment, or if you have a fever with a headache, cough, or skin rash.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Since guaifenesin and phenylephrine 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?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking guaifenesin and phenylephrine?

This medication may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Drinking alcohol can increase certain side effects of guaifenesin and phenylephrine.

Ask a doctor or pharmacist before using any other cough, cold, or allergy medicine. Guaifenesin and phenylephrine are contained in many combination medicines. Taking certain products together can cause you to get too much of a certain drug.

Guaifenesin and phenylephrine side effects

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

Guaifenesin and phenylephrine may cause serious side effects. Stop using guaifenesin and phenylephrine and call your doctor at once if you have:

• fast, pounding, or uneven heartbeat; or

• severe anxiety or nervousness.

Common side effects of guaifenesin and phenylephrine may include:

• dry mouth, nose, or throat;

• upset stomach, loss of appetite, vomiting;

• feeling excited or restless (especially in children);

• sleep problems (insomnia); or

• headache, dizziness.

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.

Guaifenesin and phenylephrine dosing information

Usual Adult Dose for Cough and Nasal Congestion:

Dose referred to by strength of guaiFENesin/phenylephrine (in mg) per unit of measurement:

Oral liquids:
100/5 per 5 mL:10 mL every 4 hours, maximum 6 doses per day

Oral tablets:
385/10 per tablet: 1 tablet every 4 hours, maximum 6 doses per day

388/10 per tablet: 1 tablet every 4 hours, maximum 6 doses per day

395/10 per tablet: 1 tablet every 4 hours, maximum 6 doses per day

Usual Pediatric Dose for Cough and Nasal Congestion:

Dose referred to by strength of guaiFENesin/phenylephrine (in mg) per unit of measurement:

Oral liquids:
50/2.5 per 1 mL:
2 to under 6 years: 1 mL every 4 hours, maximum 6 doses per day

100/5 per 5 mL:
12 years and older: 10 mL every 4 hours, maximum 6 doses per day
6 to under 12 years: 5 mL every 4 hours, maximum 6 doses per day

Oral tablets:
385/10 per tablet:
12 years and older: 1 tablet every 4 hours, maximum 6 doses per day
6 to under 12 years: 1/2 tablet every 4 hours, maximum 6 doses per day

388/10 per tablet:
12 years and older: 1 tablet every 4 hours, maximum 6 doses per day
6 to under 12 years: 1/2 tablet every 4 hours, maximum 6 doses per day

395/10 per tablet:
12 years and older: 1 tablet every 4 hours, maximum 6 doses per day
6 to under 12 years: 1/2 tablet every 4 hours, maximum 6 doses per day

What other drugs will affect guaifenesin and phenylephrine?

Ask a doctor or pharmacist before using guaifenesin and phenylephrine if you are also using any other drugs, including prescription and over-the-counter medicines, vitamins, and herbal products. Some medicines can cause unwanted or dangerous effects when used together. Not all possible interactions are listed in this medication guide.

Taking this medicine with other drugs that make you sleepy or slow your breathing can worsen these effects. Ask your doctor before taking guaifenesin and phenylephrine with a sleeping pill, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.

Further information

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.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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