What is dextromethorphan, guaifenesin, and phenylephrine?
Dextromethorphan is a 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 dextromethorphan, guaifenesin, and phenylephrine is used to treat stuffy
nose, sinus congestion, cough, and chest congestion caused by the common cold or flu.
Dextromethorphan will not treat a cough that is caused by smoking, asthma, or emphysema.
Dextromethorphan, guaifenesin, and phenylephrine may also be used for other purposes not
listed in this medication guide.
What should I discuss with my healthcare provider before taking dextromethorphan, guaifenesin, and phenylephrine?
Do not use a cough or cold medicine if you have used an MAO inhibitor such as
isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam), or
tranylcypromine (Parnate) within the past 14 days. Serious, life-threatening side effects can occur if
you take cough or cold medicine before the MAO inhibitor has cleared from your body.
Do not use this medicine if you are allergic to dextromethorphan, guaifenesin, or
phenylephrine.
Before taking this medicine, tell your doctor if you are allergic to any drugs or if you have
emphysema or chronic bronchitis. You may not be able to use this medication, or you may need a
dosage adjustment or special tests during treatment.
This medication may be harmful to an unborn baby. Tell your doctor if you are pregnant or
plan to become pregnant during treatment.
This medication may pass into breast milk and could harm a nursing baby. Do not use this
medication without telling your doctor if you are breast-feeding a baby.
Artificially-sweetened liquid forms of cold medicine may contain phenylalanine. This would be
important to know if you have phenylketonuria (PKU). Check the ingredients and warnings on the
medication label if you are concerned about phenylalanine.
How should I take dextromethorphan, guaifenesin, and phenylephrine?
Use this medication exactly as directed on the label, or as it has been prescribed by your
doctor. Do not use the medication in larger amounts, or use it for longer than recommended. Cold
medicine is usually taken only for a short time until your symptoms clear up.
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 the liquid form of this medicine with a special dose-measuring spoon or cup, not a
regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.
Take the medication with food if it upsets your stomach.
Drink extra fluids to help loosen the congestion and lubricate your throat while you are
taking this medication.
Do not crush, chew, or break an extended-release tablet. Swallow the pill whole. It is
specially made to release medicine slowly in the body. Breaking or opening the pill would cause too
much of the drug to be released at one time.
Talk with 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.
If you need to have any type of surgery, tell the surgeon ahead of time if you have taken a cold
medicine within the past few days.
Store this medicine at room temperature, away from heat, light, and moisture.
What happens if I miss a dose of dextromethorphan, guaifenesin, and phenylephrine?
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the
missed dose and take the medicine at your next regularly scheduled time.
Do not
take
extra medicine to make up the missed dose.
Where can I get more information about dextromethorphan, guaifenesin, and phenylephrine?
Your pharmacist has information about dextromethorphan, guaifenesin, and phenylephrine written for health professionals that you may read.
What are the possible side effects of dextromethorphan, guaifenesin, and phenylephrine?
Get emergency medical help if you have any of these
signs of an allergic
reaction:
hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Stop using this medication and call your doctor at once if you have any of these serious side
effects:
-
severe dizziness, anxiety, restless feeling, or nervousness;
-
confusion, hallucinations; or
-
slow, shallow breathing.
Less serious side effects may include:
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. You may report side effects to FDA at 1-800-FDA-1088.
What is the most important information I should know about dextromethorphan, guaifenesin, and phenylephrine?
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.
Do not use a cough or cold medicine if you have used an MAO inhibitor such as
isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam), or
tranylcypromine (Parnate) within the past 14 days. Serious, life-threatening side effects can occur if
you take cough or cold medicine before the MAO inhibitor has cleared from your body.
Do not use any other over-the-counter cough, cold, allergy, or sleep medication without
first asking your doctor or pharmacist. If you take certain products together you may accidentally take
too much of one or more types of medicine. Read the label of any other medicine you are using to see
if it contains a decongestant, expectorant, or cough suppressant.
Dextromethorphan will not treat a cough that is caused by smoking, asthma, or emphysema.
What should I avoid while taking dextromethorphan, guaifenesin, and phenylephrine?
This medication can cause side effects that may impair your thinking or reactions. Be
careful if you drive or do anything that requires you to be awake and alert.
Avoid drinking alcohol. It can increase some of the side effects of this medication.
Avoid taking diet pills, caffeine pills, or other stimulants (such as ADHD medications) without
your doctor's advice. Taking a stimulant together with cough or cold medicine can increase your risk
of unpleasant side effects.
Do not use any other over-the-counter cough, cold, allergy, or sleep medication without
first asking your doctor or pharmacist. If you take certain products together you may accidentally take
too much of one or more types of medicine. Read the label of any other medicine you are using to see
if it contains a decongestant, expectorant, or cough suppressant.
What other drugs will affect dextromethorphan, guaifenesin, and phenylephrine?
Before taking dextromethorphan, guaifenesin, and phenylephrine, tell your doctor if you are
using any of the following drugs:
-
celecoxib (Celebrex);
-
cinacalcet (Sensipar);
-
darifenacin (Enablex);
-
imatinib (Gleevec);
-
quinidine (Quinaglute, Quinidex);
-
ranolazine (Ranexa)
-
ritonavir (Norvir);
-
sibutramine (Meridia);
-
terbinafine (Lamisil);
-
medicines to treat high blood pressure; or
-
antidepressant medications such as amitriptyline (Elavil,
Etrafon), bupropion (Wellbutrin, Zyban), fluoxetine (Prozac, Sarafem), fluvoxamine (Luvox),
imipramine (Janimine, Tofranil), paroxetine (Paxil), sertraline (Zoloft), and others.
This list is not complete and there may be other drugs that can interact with
dextromethorphan, guaifenesin, and phenylephrine. Tell your doctor about all the prescription and
over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs
prescribed by other doctors. Do not start using a new medication without telling your doctor.
What happens if I have an overdose of dextromethorphan, guaifenesin, and phenylephrine?