Pronunciation: FEN il EFF rin

Brand: Dimetapp Cold Drops, Nasop, Nasop12, Sudafed PE, Sudafed PE Children's Nasal Decongestant, Sudogest PE

What is the most important information I should know about phenylephrine?

Do not use phenylephrine if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others.

What is phenylephrine?

Phenylephrine is a decongestant that shrinks blood vessels in the nasal passages. Dilated blood vessels can cause nasal congestion (stuffy nose).

Phenylephrine is used to treat nasal and sinus congestion, or congestion of the tubes that drain fluid from your inner ears, called the eustachian (yoo-STAY-shun) tubes.

Phenylephrine may also be used for purposes not listed in this medication guide.

What should I discuss with my healthcare provider before taking phenylephrine?

Do not use phenylephrine if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others.

You should not not use this medicine if you are allergic to phenylephrine or to other decongestants.

Ask a doctor or pharmacist if it is safe for you to take phenylephrine if you have:

  • heart disease or high blood pressure;
  • diabetes; or
  • a thyroid disorder.

It is not known whether phenylephrine will harm an unborn baby. Do not use this medicine without a doctor's advice if you are pregnant.

Phenylephrine can pass into breast milk and may harm a nursing baby. Do not use this medicine without a doctor's advice if you are breast-feeding a baby.

Artificially sweetened liquid medicine may contain phenylalanine. Check the medication label if you have phenylketonuria (PKU).

How should I take phenylephrine?

Use exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended. Cold medicine is usually taken only for a short time until your symptoms clear up.

Do not give this medication to a child younger than 4 years old. 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.

Take this medicine with a full glass of water.

The chewable tablet must be chewed before you swallow it.

You may need to shake the oral suspension (liquid) well just before you measure a dose. Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

If you need surgery, tell the surgeon ahead of time that you are using phenylephrine. You may need to stop using the medicine for a short time.

Call 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.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Since phenylephrine is used when needed, you may not be on a dosing schedule. If you are on a schedule, use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking phenylephrine?

Ask a doctor or pharmacist before using any other cough or cold medicine. Phenylephrine or other decongestants are contained in many combination medicines. Taking certain products together can cause you to get too much of a certain drug. Check the label to see if a medicine contains phenylephrine or a decongestant.

What are the possible side effects of phenylephrine?

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using phenylephrine and call your doctor at once if you have:

  • fast, pounding, or uneven heartbeat;
  • severe dizziness or anxiety;
  • easy bruising or bleeding, unusual weakness, fever, chills, body aches, flu symptoms; or
  • dangerously high blood pressure (severe headache, blurred vision, ringing in your ears, anxiety, confusion, chest pain, trouble breathing, uneven heart rate, seizure).

Common side effects may include:

  • loss of appetite;
  • warmth, tingling, or redness under your skin;
  • feeling restless or excited (especially in children);
  • sleep problems (insomnia); or
  • 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.

What other drugs will affect phenylephrine?

Ask a doctor or pharmacist before using this medicine if you are also using any other drugs, including prescription and over-the-counter medicines, vitamins, and herbal products. Some medicines can cause unwanted or dangerous effects when used together. Not all possible interactions are listed in this medication guide.

Taking this medicine with other drugs that make you sleepy or slow your breathing can worsen these effects. Ask your doctor before taking phenylephrine with a sleeping pill, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.

Where can I get more information?

Your pharmacist can provide more information about phenylephrine.


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.

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