Sudafed Drug Profile and Side Effects

Sudafed is nasal decongestant used to treat congestion. Because it was being widely abused as a raw ingredient in methamphetamines, Sudafed is now located behind the counter, but it doesn't require a prescription. Simply ask your pharmacist, show a photo ID and sign upon purchase.

Woman in bed blowing her nose
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Sudafed PE, however, is sold on drugstore shelves. That's because Sudafed and Sudafed PE are made with different formulations. In 2006 the FDA passed a law that requires Sudafed to be sold behind the counter because its active ingredient is pseudoephedrine, which is used to manufacture illegal methamphetamines. Sudafed PE, however, is available over-the-counter. Its active ingredient is phenylephrine.

What Is Sudafed?

The active ingredient in Sudafed, pseudoephedrine, is used to alleviate nasal congestion caused by allergies, colds, and other upper respiratory illnesses. It can also be used to relieve sinus congestion and pressure caused by sinusitis, or a sinus infection.

Congestion occurs when blood vessels in the nasal passages and airways swell and expand, becoming inflamed. Sudafed works by shrinking the blood vessels back to their normal size to allow more airflow and mucus to drain. It is used to relieve symptoms, not to treat the causes of symptoms or to speed up recovery.

Adults and children over 12 years old should take two caplets every 4 to 6 hours, not to exceed four doses in 24 hours. Children ages 6 to 12 years old should take one caplet every 4 to 6 hours, not to exceed four doses in 24 hours. Children under 6 years should never take Sudafed unless directed to do so by a healthcare provider. Sudafed should also be swallowed whole. Do not crush or chew Sudafed.

Common Side Effects

  • Confusion
  • Nervous feeling
  • Headache
  • Nausea
  • Vomiting
  • Loss of appetite
  • Restlessness
  • Dizziness
  • Stomach pain
  • Difficulty breathing
  • A fast, pounding or irregular heartbeat
  • Nervousness
  • Sleeplessness
  • Nasal congestion that lasts for more than seven days or is accompanied by a fever
  • Heart disease
  • High blood pressure
  • Thyroid disease
  • Diabetes
  • Prostate issues

Sudafed and other decongestants typically do not cause any side effects, and if side effects occur, they're usually mild. Still, it's important to know that side effects are possible. The chemical formulation of Sudafed is similar to adrenaline, which, in addition to acting as a natural decongestant, is also a stimulant. Taking a decongestant such as Sudafed can make a person feel jittery, and it can also impact a person's blood pressure, pulse and ability to fall asleep, although this isn't common. Other side effects of Sudafed are more serious. If you experience any of the following, contact your healthcare provider immediately:

Should Anyone Not Take Sudafed?

Sudafed and other decongestants are safe for most people, but there are some exceptions. Do not take Sudafed without your healthcare provider's permission if you have any of the following: Additionally, you should not use Sudafed if you are currently taking an MAOI or for the 2 weeks after you stop the use of an MAOI. If you have any questions or hesitations, talk to your healthcare provider or pharmacist before taking this medication.

Keep Sudafed and all other medications, for that matter, out of reach of children. In the case of an overdose, contact Poison Control or visit an emergency room immediately.

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4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Eccles R. Substitution of phenylephrine for pseudoephedrine as a nasal decongeststant. An illogical way to control methamphetamine abuseBr J Clin Pharmacol. 2007;63(1):10–14. doi:10.1111/j.1365-2125.2006.02833.x

  3. Deckx L, Sutter AID, Guo L, Mir NA, Driel MLV. Nasal decongestants in monotherapy for the common coldCochrane Database of Systematic Reviews. 2016. doi:10.1002/14651858.cd009612.pub2

  4. Laccourreye O, Werner A, Giroud J-P, Couloigner V, Bonfils P, Bondon-Guitton E. Benefits, limits and danger of ephedrine and pseudoephedrine as nasal decongestantsEuropean Annals of Otorhinolaryngology, Head and Neck Diseases. 2015;132(1):31-34. doi:10.1016/j.anorl.2014.11.001

Additional Reading
  • "Products/Sudafed Nasal Decongestant." Sudafed & Sudafed PE. 2005. Pfizer Inc. 22 Jan 2007.
  • NHS Choices.Decongestants. (2016, March 03).