What is diphenhydramine and phenylephrine?
Diphenhydramine is an antihistamine that reduces the natural chemical histamine in the body.
Histamine can produce symptoms of sneezing, itching, watery eyes, and runny nose.
Phenylephrine is a decongestant that shrinks blood vessels in the nasal passages. Dilated blood
vessels can cause nasal congestion (stuffy nose).
The combination of diphenhydramine and phenylephrine is used to treat runny or stuffy nose,
sneezing, watery eyes, and sinus congestion caused by allergies, the common cold, or the flu.
Diphenhydramine 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 diphenhydramine and phenylephrine?
You should not use this medication if you are allergic to diphenhydramine or phenylephrine.
Before taking this medication, tell your doctor if you are allergic to any drugs, or if you have:
If you have any of these conditions, you may need a dose adjustment or
special tests to safely take this medication.
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.
Older adults may be more likely to have side effects from this medication.
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 diphenhydramine 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.
Make sure you chew the chewable tablet before you swallow it.
This medication can cause you to have unusual results with allergy skin tests. Tell any doctor
who treats you that you are taking an antihistamine.
Store this medicine at room temperature, away from heat, light, and moisture.
What happens if I miss a dose of diphenhydramine and phenylephrine?
Since cold or allergy 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 diphenhydramine and phenylephrine?
Your pharmacist has information about diphenhydramine and phenylephrine written for health professionals that you may read.
What are the possible side effects of diphenhydramine 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:
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fast, pounding, or uneven heartbeat;
-
confusion, hallucinations, unusual thoughts or behavior;
-
urinating less than usual or not at all;
-
severe dizziness, anxiety, restless feeling, or nervousness;
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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); or
-
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:
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blurred vision;
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dry mouth;
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nausea, stomach pain, constipation;
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dizziness, drowsiness;
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problems with memory or concentration;
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ringing in your ears;
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mild loss of appetite;
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warmth, tingling, or redness under your skin;
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feeling excited or restless;
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sleep problems (insomnia); or
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skin rash or itching.
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 diphenhydramine 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.
Avoid drinking alcohol while you are taking this medication. It can add to drowsiness
caused by an antihistamine.
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.
Tell your doctor if you regularly use other medicines that make you sleepy (such as other
cold or allergy medicine, narcotic pain medicine, sleeping pills, muscle relaxers, and medicine for
seizures, depression, or anxiety). They can add to sleepiness caused by diphenhydramine.
What should I avoid while taking diphenhydramine and phenylephrine?
Avoid drinking alcohol while you are taking this medication. It can add to drowsiness
caused by an antihistamine.
Tell your doctor if you regularly use other medicines that make you sleepy (such as other
cold or allergy medicine, narcotic pain medicine, sleeping pills, muscle relaxers, and medicine for
seizures, depression, or anxiety). They can add to sleepiness caused by diphenhydramine.
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.
Avoid becoming overheated or dehydrated during exercise and in hot weather.
Do not use any other over-the-counter cough, cold, allergy, or sleep medication without
first asking your doctor or pharmacist. Antihistamines, decongestants, and cough suppressants are
contained in many medicines available over the counter. 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 other drugs will affect diphenhydramine and phenylephrine?
Tell your doctor about all other medications you use, especially:
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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;
-
antidepressants such as amitriptyline (Elavil), clomipramine
(Anafranil), imipramine (Janimine, Tofranil), and others; or
-
an MAO inhibitor such as isocarboxazid (Marplan),
phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam), or tranylcypromine
(Parnate).
This list is not complete and there may be other drugs that can interact with
diphenhydramine 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 diphenhydramine and phenylephrine?
