What is guaifenesin and phenylephrine?
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 guaifenesin and phenylephrine is 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 other purposes not listed in this
medication guide.
What should I discuss with my healthcare provider before taking guaifenesin and phenylephrine?
Do not use this medication if you are allergic to guaifenesin or phenylephrine, or to
other decongestants, diet pills, stimulants, or ADHD medications.
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.
Before taking this medication, tell your doctor if you have
If you have any of these conditions, you may not be able to use this
medication, or you may need a dosage adjustment or special tests during treatment.
FDA pregnancy category C. 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 passes 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.
This medication may be harmful to an unborn baby. Tell your doctor if you are
pregnant or plan to become pregnant during treatment.
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 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.
Do not crush, chew, break, or open a controlled-release, delayed-release, or
extended-release tablet or capsule. 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.
Take guaifenesin and phenylephrine with food if it upsets your stomach.
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.
Drink extra fluids to help loosen the congestion and lubricate your throat while you
are taking this medication.
What happens if I miss a dose of guaifenesin and phenylephrine?
Since cough or cold medicine is usually taken only as 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. 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 guaifenesin and phenylephrine?
Your pharmacist has information about guaifenesin and phenylephrine written for health professionals that you may read.
What are the possible side effects of 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:
-
fast, pounding, or uneven heartbeat;
-
severe dizziness, anxiety, restless feeling, or nervousness;
-
easy bruising or bleeding, unusual weakness, fever, chills,
body aches, flu symptoms;
-
increased blood pressure (severe headache, blurred vision,
trouble concentrating, chest pain, numbness, seizure);
-
nausea, stomach pain, low fever, loss of appetite, dark
urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
Less serious side effects may include:
-
nausea, vomiting, upset stomach, loss of appetite;
-
warmth, tingling, or redness under your skin;
-
feeling excited or restless;
-
sleep problems (insomnia);
-
skin rash or itching;
-
headache; or
-
dizziness.
Side effects other than those listed here may also occur. Talk to your
doctor about any side effect that seems unusual or that is especially bothersome. You may report side effects to FDA at 1-800-FDA-1088.
What is the most important information I should know about 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 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 an antihistamine, decongestant, or cough suppressant.
What should I avoid while taking guaifenesin and phenylephrine?
Avoid drinking alcohol while you are taking this medicine.
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 an antihistamine, decongestant, or cough suppressant.
Avoid taking diet pills, caffeine pills, or other stimulants (such as ADHD medications)
without your doctor's advice. Taking a stimulant together with a decongestant can increase your
risk of unpleasant side effects.
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.
What other drugs will affect guaifenesin and phenylephrine?
Before taking this medication, tell your doctor if you use any of the following drugs:
-
medicines to treat high blood pressure;
-
a beta-blocker such as atenolol (Tenormin), carteolol
(Cartrol), metoprolol (Lopressor, Toprol), nadolol (Corgard), propranolol (Inderal), sotalol
(Betapace), timolol (Blocadren), and others; or
-
antidepressants such as amitriptyline (Elavil),
clomipramine (Anafranil), imipramine (Janimine, Tofranil), and others.
This is not a complete list and there may be other drugs that can
interact with 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. Keep a list with you of all the medicines you use and show this list to any doctor or other
healthcare provider who treats you.
What happens if I have an overdose of guaifenesin and phenylephrine?