Skip to Content

The originating document has been archived. We cannot confirm the completeness, accuracy and currency of the content.

Sudafed 12-Hour

Generic Name: pseudoephedrine (SOO doe ee FED rin)
Brand Name: Chlor Trimeton Nasal Decongestant, Contac Cold, Drixoral Decongestant Non-Drowsy, Elixsure Decongestant, Entex, Genaphed, Kid Kare Drops, Nasofed, Seudotabs, Silfedrine, Sudafed, Sudafed 12-Hour, Sudafed 24-Hour, Sudafed Children's Nasal Decongestant, Sudodrin, SudoGest, SudoGest 12 Hour, Suphedrin, Triaminic Softchews Allergy Congestion, Unifed

Medically reviewed on February 1, 2018.

What is Sudafed 12-Hour (pseudoephedrine)?

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

Pseudoephedrine 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.

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

What is the most important information I should know about Sudafed 12-Hour (pseudoephedrine)?

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.

Ask a doctor or pharmacist before using any other cough or cold medicine. Pseudoephedrine 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 pseudoephedrine or a decongestant.

Do not use pseudoephedrine if you have used an MAO inhibitor such as furazolidone (Furoxone), isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam, Zelapar), or tranylcypromine (Parnate) in the last 14 days. A dangerous drug interaction could occur, leading to serious side effects.

What should I discuss with my healthcare provider before taking Sudafed 12-Hour (pseudoephedrine)?

Do not use pseudoephedrine if you have used an MAO inhibitor such as furazolidone (Furoxone), isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam, Zelapar), or tranylcypromine (Parnate) in the last 14 days. A dangerous drug interaction could occur, leading to serious side effects.

Do not use this medication if you are allergic to pseudoephedrine or to other decongestants, diet pills, stimulants, or ADHD medications.

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

  • heart disease or high blood pressure;

  • diabetes; or

  • a thyroid disorder.

FDA pregnancy category C. It is not known whether pseudoephedrine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication.

Pseudoephedrine can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

Artificially sweetened liquid cold medicine may contain phenylalanine. If you have phenylketonuria (PKU), check the medication label to see if the product contains phenylalanine.

How should I take Sudafed 12-Hour (pseudoephedrine)?

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.

Do not crush, chew, or break an extended-release tablet. Swallow it whole. Breaking or opening the pill may cause too much of the drug to be released at one time.

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

Do not take pseudoephedrine for longer than 7 days in a row. 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 surgery, tell the surgeon ahead of time that you are using pseudoephedrine. You may need to stop using the medicine for a short time.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Since pseudoephedrine is taken 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. Skip the missed dose if it is almost time for your next scheduled dose. Do not take 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.

Overdose symptoms may include feeling restless or nervous.

What should I avoid while taking Sudafed 12-Hour (pseudoephedrine)?

Avoid taking this medication if you also take diet pills, caffeine pills, or other stimulants (such as ADHD medications). Taking a stimulant together with a decongestant can increase your risk of unpleasant side effects.

Ask a doctor or pharmacist before using any other cough or cold medicine. Pseudoephedrine 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 pseudoephedrine or a decongestant.

Sudafed 12-Hour (pseudoephedrine) side effects

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 pseudoephedrine and call your doctor at once if you have a serious side effect such as:

  • 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).

Less serious 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.

See also: Side effects (in more detail)

What other drugs will affect Sudafed 12-Hour (pseudoephedrine)?

Tell your doctor about all other medicines you use, especially:

  • blood pressure medications;

  • a beta blocker such as atenolol (Tenormin, Tenoretic), carvedilol (Coreg), labetalol (Normodyne, Trandate), metoprolol (Dutoprol, Lopressor, Toprol), nadolol (Corgard), propranolol (Inderal, InnoPran), sotalol (Betapace), and others; or

  • an antidepressant such as amitriptyline (Elavil, Vanatrip, Limbitrol), doxepin (Sinequan), nortriptyline (Pamelor), and others.

This list is not complete and other drugs may interact with pseudoephedrine. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.

Further information

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.

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

Hide