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Diphenhydramine and Phenylephrine Liquid, Solution, and Syrup

Generic Name: Diphenhydramine and Phenylephrine Liquid, Solution, and Syrup (dye fen HYE dra meen & fen il EF rin)
Brand Name: Alahist LQ, PediaCare Children's NightRest

Medically reviewed on May 2, 2018

Uses of Diphenhydramine and Phenylephrine Liquid, Solution, and Syrup:

  • It is used to treat nose stuffiness.
  • It is used to ease allergy signs.

What do I need to tell my doctor BEFORE I take Diphenhydramine and Phenylephrine Liquid, Solution, and Syrup?

  • If you have an allergy to diphenhydramine, phenylephrine, or any other part of diphenhydramine and phenylephrine liquid, solution, and syrup.
  • If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
  • If you have taken certain drugs used for low mood (depression) like isocarboxazid, phenelzine, or tranylcypromine or drugs used for Parkinson's disease like selegiline or rasagiline in the last 14 days. Taking diphenhydramine and phenylephrine liquid, solution, and syrup within 14 days of those drugs can cause very bad high blood pressure.

This is not a list of all drugs or health problems that interact with diphenhydramine and phenylephrine liquid, solution, and syrup.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take diphenhydramine and phenylephrine liquid, solution, and syrup with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take Diphenhydramine and Phenylephrine Liquid, Solution, and Syrup?

  • Tell all of your health care providers that you take diphenhydramine and phenylephrine liquid, solution, and syrup. This includes your doctors, nurses, pharmacists, and dentists.
  • Do not take more than what your doctor told you to take. Taking more than you are told may raise your chance of very bad side effects.
  • Do not take diphenhydramine and phenylephrine liquid, solution, and syrup for longer than you were told by your doctor.
  • Avoid driving and doing other tasks or actions that call for you to be alert until you see how diphenhydramine and phenylephrine liquid, solution, and syrup affects you.
  • Avoid drinking alcohol while taking diphenhydramine and phenylephrine liquid, solution, and syrup.
  • Talk with your doctor before you use other drugs and natural products that slow your actions.
  • Do not use with other products that have diphenhydramine.
  • Use with care in children. Talk with the doctor.
  • Different brands of diphenhydramine and phenylephrine liquid, solution, and syrup may have different doses for children. Talk with the doctor before giving diphenhydramine and phenylephrine liquid, solution, and syrup to a child.
  • If you are 65 or older, use diphenhydramine and phenylephrine liquid, solution, and syrup with care. You could have more side effects.
  • Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using diphenhydramine and phenylephrine liquid, solution, and syrup while you are pregnant.
  • Tell your doctor if you are breast-feeding. You will need to talk about any risks to your baby.

How is this medicine (Diphenhydramine and Phenylephrine Liquid, Solution, and Syrup) best taken?

Use diphenhydramine and phenylephrine liquid, solution, and syrup as ordered by your doctor. Read all information given to you. Follow all instructions closely.

  • Take with or without food. Take with food if it causes an upset stomach.
  • Measure liquid doses carefully. Use the measuring device that comes with diphenhydramine and phenylephrine liquid, solution, and syrup. If there is none, ask the pharmacist for a device to measure diphenhydramine and phenylephrine liquid, solution, and syrup.

What do I do if I miss a dose?

  • If you take diphenhydramine and phenylephrine liquid, solution, and syrup on a regular basis, take a missed dose as soon as you think about it.
  • If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
  • Do not take 2 doses at the same time or extra doses.
  • Many times diphenhydramine and phenylephrine liquid, solution, and syrup is taken on an as needed basis. Do not take more often than told by the doctor.

See also: Dosage Information (in more detail)

What are some side effects that I need to call my doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.

What are some other side effects of Diphenhydramine and Phenylephrine Liquid, Solution, and Syrup?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

  • Dizziness.
  • Feeling nervous and excitable.
  • Not able to sleep.
  • Feeling sleepy.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch.

See also: Side effects (in more detail)

If OVERDOSE is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

How do I store and/or throw out Diphenhydramine and Phenylephrine Liquid, Solution, and Syrup?

  • Store at room temperature.
  • Protect from light.
  • Store in a dry place. Do not store in a bathroom.
  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.

Consumer information use

  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else's drugs.
  • Keep a list of all your drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your doctor.
  • Talk with the doctor before starting any new drug, including prescription or OTC, natural products, or vitamins.
  • Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about diphenhydramine and phenylephrine liquid, solution, and syrup, please talk with your doctor, nurse, pharmacist, or other health care provider.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

Further information

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

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