Skip to Content

Guaifenesin, hydrocodone, and phenylephrine

Generic Name: guaifenesin, hydrocodone, and phenylephrine (gwye FEH neh sin , high droe KOE dohn , and feh nill EH frin)
Brand Name: De-Chlor G, Hydro GP, Nariz HC, Nazarin HC, Simuc-HD, ...show all 23 brand names

Medically reviewed by Drugs.com on Oct 1, 2018 – Written by Cerner Multum

What is guaifenesin, hydrocodone, and phenylephrine?

Guaifenesin, hydrocodone, and phenylephrine is a combination medicine used to treat cough, stuffy nose, and sinus congestion caused by the common cold.

Guaifenesin, hydrocodone, and phenylephrine contains a narcotic cough medicine and may be habit-forming.

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

Important Information

MISUSE OF guaifenesin, hydrocodone, and phenylephrine CAN CAUSE ADDICTION, OVERDOSE, OR DEATH. Keep the medication in a place where others cannot get to it.

Fatal side effects can occur if you use this medicine with alcohol, or with other drugs that cause drowsiness or slow your breathing.

Before taking this medicine

You should not use this medicine if you are allergic to guaifenesin, hydrocodone, or phenylephrine, or if you have:

Do not give this medicine to anyone younger than 6 years old.

Do not use this medicine if you have used an MAO inhibitor in the past 14 days, such as isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, or tranylcypromine.

Tell your doctor if you have ever had:

If you use hydrocodone while you are pregnant, your baby could become dependent on the drug. This can cause life-threatening withdrawal symptoms in the baby after it is born. Babies born dependent on habit-forming medicine may need medical treatment for several weeks. Tell your doctor if you are pregnant or plan to become pregnant.

Do not breast-feed. Hydrocodone can pass into breast milk and may cause drowsiness, breathing problems, or death in a nursing baby.

How should I take guaifenesin, hydrocodone, and phenylephrine?

Follow the directions on your prescription label and read all medication guides. Never use guaifenesin, hydrocodone, and phenylephrine in larger amounts, or for longer than prescribed. Use the medicine only until your symptoms clear up.

Never share this medicine with another person, especially someone with a history of drug abuse or addiction. MISUSE CAN CAUSE ADDICTION, OVERDOSE, OR DEATH. Keep the medicine in a place where others cannot get to it. Selling or giving away this medicine is against the law.

Measure liquid medicine carefully. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon). Rinse after each use.

Call your doctor if your symptoms do not improve after 5 days, or if you have a fever, rash, or headaches.

If you need surgery or medical tests, tell the surgeon or doctor ahead of time if you have taken a cough or cold medicine within the past few days.

Store at room temperature away from moisture and heat. Do not freeze.

Do not keep leftover medication. Just one dose can cause death in someone using this medicine accidentally or improperly. Read and carefully follow the instructions provided with this medicine about how to safely dispose of any unused portion.

What happens if I miss a dose?

Since this medicine is used when needed, you may not be on a dosing schedule. Skip any missed dose if it's almost time for your next dose. Do not use two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. A hydrocodone overdose can be fatal, especially in a child or other person using the medicine without a prescription. Overdose symptoms may include slow breathing and heart rate, severe drowsiness, muscle weakness, cold and clammy skin, pinpoint pupils, and fainting.

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

Do not drink alcohol. Dangerous side effects or death could occur.

Avoid driving or operating machinery until you know how guaifenesin, hydrocodone, and phenylephrine will affect you. Dizziness or severe drowsiness can cause falls or other accidents.

Guaifenesin, hydrocodone, 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.

This medicine can slow or stop your breathing, and death may occur. A person caring for you should seek emergency medical attention if you have slow breathing with long pauses, blue colored lips, or if you are hard to wake up.

Stop taking this medicine and call your doctor at once if you have:

  • noisy breathing, sighing, shallow breathing;

  • extreme drowsiness, confusion, feeling weak or limp;

  • a seizure;

  • a light-headed feeling, like you might pass out;

  • severe constipation;

  • little or no urination; or

  • adrenal gland problems--nausea, vomiting, loss of appetite, dizziness, worsening tiredness or weakness.

Seek medical attention right away if you have symptoms of serotonin syndrome, such as: agitation, hallucinations, fever, sweating, shivering, fast heart rate, muscle stiffness, twitching, loss of coordination, nausea, vomiting, or diarrhea.

Serious side effects may be more likely in older adults and those who are overweight, malnourished, or debilitated.

Long-term use of opioid medication may affect fertility (ability to have children) in men or women. It is not known whether opioid effects on fertility are permanent.

Common side effects may include:

  • drowsiness, dizziness;

  • lack of energy, coordination problems;

  • headache, confusion;

  • dry mouth, nausea, vomiting, constipation;

  • tremors, fast or irregular heart rate; or

  • feeling anxious, restless, nervous, or irritable.

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 guaifenesin, hydrocodone, and phenylephrine?

You may have breathing problems or withdrawal symptoms if you start or stop taking certain other medicines. Tell your doctor if you also use certain antibiotics, antifungal medications, seizure medication, or medicines to treat HIV or hepatitis C.

Using guaifenesin, hydrocodone, and phenylephrine with other drugs that slow your breathing can cause dangerous side effects or death. Ask your doctor before using opioid medication, a sleeping pill, a muscle relaxer, or medicine for anxiety or seizures.

Tell your doctor about all your current medicines. Many drugs can affect guaifenesin, hydrocodone, and phenylephrine, especially:

  • a sedative like Xanax or Valium (diazepam, alprazolam, lorazepam, and others);

  • other cough, cold, or allergy medicines;

  • asthma medication;

  • pain medicine or a muscle relaxer;

  • medicine to treat depression, anxiety, mood disorders, or mental illness;

  • heart or blood pressure medication;

  • a diuretic or "water pill";

  • bladder or urinary medicines; or

  • medicine to treat stomach problems.

This list is not complete and many other drugs may affect guaifenesin, hydrocodone, and phenylephrine. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

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.

Hide