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Pseudoephedrine: 7 things you should know

Medically reviewed by Carmen Pope, BPharm. Last updated on Aug 30, 2023.

1. How it works

  • Pseudoephedrine is a decongestant that constricts (shrinks) dilated blood vessels within the nose, relieving congestion.
  • It causes vasoconstriction by stimulating primarily alpha-adrenergic receptors. It also has weak activity at beta-adrenergic receptors. It is chemically related to ephedrine, but with less central nervous system activity (fewer effects on the brain).
  • Pseudoephedrine belongs to the class of medicines known as nasal decongestants. It may also be called a sympathomimetic.

2. Upsides

  • May be used to treat nasal congestion, sinus congestion, and other respiratory conditions. Tablets, chewable tablets, liquid and nasal preparations of pseudoephedrine effectively treat nasal and sinus congestion; however, the sale of cold and flu products containing pseudoephedrine is limited to behind the counter because pseudoephedrine may be used for the illicit production of methamphetamine.
  • May be given to prevent otitic barotrauma (ear pain due to rapid changes in air pressure) in air travelers (one 120mg extended-release tablet should be taken 30 minutes before departure) and divers (60mg taken 30 minutes before diving).
  • Significantly more effective as a decongestant than phenylephrine.
  • May be used in addition to pain relievers, antihistamines, cough suppressants, expectorants, or antibiotics.
  • Some manufacturers have reformulated cough and cold preparations to contain phenylephrine rather than pseudoephedrine.
  • Extended-release tablets may be administered once daily. Immediate-release tablets need to be given every 4 to 6 hours.
  • Generic pseudoephedrine is available.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Sleep disturbances, restlessness, rash or itching, loss of appetite, feeling of warmth or redness under the skin.
  • May not be suitable for some people including those with high blood pressure, heart disease, diabetes, prostatic hyperplasia or urinary obstruction, kidney disease, a seizure disorder, increased ocular pressure or angle-closure glaucoma, known sensitivity to sympathomimetic drugs, or a thyroid disorder. Do not use pseudoephedrine if you are pregnant or breastfeeding unless under a doctor's advice.
  • May interact with some other medications including monoamine oxidase inhibitors, blood pressure medications, beta-blockers, and antidepressants.
  • Not suitable for children under four. Always talk with a doctor before giving cough or cold medicines to children under the age of 12 years.
  • Older patients over the age of 60 years may be more sensitive to the effects of pseudoephedrine.
  • Will cause a false-positive result on a urine test for amphetamines.
  • Potential for abuse and misuse.
  • Individuals purchasing pseudoephedrine must produce a photo ID and supply personal information that the store must keep for at least two years. The quantity that can be purchased is also limited.
  • May be used for the clandestine manufacture of methamphetamine and methcathinone.
  • The use of pseudoephedrine in some states may be subject to additional controls.
  • Extended-release tablets have been associated with rare reports of GI obstruction.
  • Treatment with pseudoephedrine should be discontinued if symptoms persist for more than 7 days or are accompanied by fever.
  • May not be suitable during pregnancy or breastfeeding; weigh up benefits versus risks.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

  • Pseudoephedrine effectively relieves nasal congestion and is found in several behind the counter combination cold and flu remedies. Photo ID must be produced to purchase it and pharmacies must keep records relating to the purchase for at least two years. Sleeplessness is a common side effect.

5. Tips

  • Use as directed for short periods only (no more than seven days). Pseudoephedrine only provides symptom relief, it does not cure a cold.
  • Take it with a full glass of water.
  • Chew the chewable tablet before swallowing. Shake the oral suspension well before measuring out the correct dose. Always use a proper measuring spoon or dropper to ensure you are getting the correct dose. Swallow extended-release capsules whole, do not break them open or chew. Some tablets may not fully dissolve and the tablet shell may be visible in the stool. This is normal and the active contents of the tablet will have been absorbed by your body.
  • Do not give pseudoephedrine to children without talking to a doctor first. Pseudoephedrine must never be given to children under the age of four.
  • Call your doctor if your symptoms have not improved within seven days of treatment, or if you develop a fast, pounding, or uneven heartbeat, severe dizziness or anxiety, severe headache, an allergic reaction, fever, or rash. Stop taking pseudoephedrine if you experience nervousness, dizziness, or insomnia during treatment.
  • Talk to your doctor or pharmacist before using any other cold or flu remedies as they may also contain pseudoephedrine or another decongestant.
  • Avoid taking pseudoephedrine if you also take caffeine supplements, diet pills, or other stimulants (such as ADHD medications).
  • Tell your doctor if you are pregnant or planning to become pregnant because pseudoephedrine may not be suitable for you.

6. Response and effectiveness

  • The decongestant effect of pseudoephedrine is noticeable within 30 minutes of oral administration and reaches a peak within one to two hours. One immediate-release tablet of pseudoephedrine lasts anywhere from three to eight hours.
  • Single doses of 60mg pseudoephedrine are effective at relieving congestion.

7. Interactions

Medicines that interact with pseudoephedrine may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with pseudoephedrine. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with pseudoephedrine include:

  • antidepressants, such as amitriptyline, amoxapine, clomipramine, doxepin, imipramine, isocarboxazid, or phenelzine
  • atomoxetine
  • atropine
  • benztropine
  • beta-blockers, such as atenolol or sotalol
  • bromocriptine
  • diabetes medications, such as metformin, glimepiride, glipizide, glyburide, or insulin
  • digoxin
  • duloxetine
  • heart medications, such as atenolol, betaxolol, bisoprolol, carvedilol
  • levodopa
  • linezolid
  • methyldopa
  • methylene blue
  • methylphenidate
  • migraine medications, such as dihydroergotamine or ergotamine
  • monoamine oxidase inhibitors such as phenelzine, isocarboxazid, or selegiline (allow at least two weeks to elapse between discontinuation of an MAOI and initiation of pseudoephedrine)
  • oxybutynin
  • orphenadrine
  • potassium citrate
  • reserpine
  • selegiline
  • venlafaxine.

Note that this list is not all-inclusive and includes only common medications that may interact with pseudoephedrine. You should refer to the prescribing information for pseudoephedrine for a complete list of interactions.


Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use pseudoephedrine only for the indication prescribed.

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

Copyright 1996-2023 Revision date: August 30, 2023.