Reviewed by: HU Medical Review Board | Last reviewed: September 2022

Decongestants provide fast, temporary relief for a stuffy nose. Your doctor may call this nasal or sinus congestion. Decongestants come in many forms, including:1-3

  • Pills
  • Nasal sprays
  • Eye drops
  • Liquids

There are many different types of decongestants. These drugs differ by their formulation, how long they last, and their side effects. Most are available over-the-counter.1-3

Decongestants are a short-term remedy for allergy symptoms. Decongestants are different from antihistamines. Antihistamines help with allergy symptoms by blocking the action of histamine. Decongestants relieve congestion even if it is not caused by allergies.3,4

Decongestants may be combined with antihistamines to clear a stuffy nose and relieve other allergy symptoms like sneezing, wheezing, and itchy eyes.3

How do decongestants work?

Decongestants are a group of drugs that narrow blood vessels in the nasal passages. This reduces swelling and inflammation, which makes it easier to breathe through the nose.1-4

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Types of decongestants

The 2 most common active ingredients in decongestants are phenylephrine and pseudoephedrine. Oxymetazoline and tetrahydrozoline are other ingredients that may be used. Pseudoephedrine is often sold behind the counter and sometimes requires a prescription.2-4

Examples of decongestants include:1,3

  • Oxymetazoline (Afrin®, Zicam®)
  • Phenylephrine (Contac-D®, Neo-Synephrine®, Sudafed® PE)
  • Pseudoephedrine (Nexafed®, Sudafed®)
  • Tetrahydrozoline (Tyzine®)

Some allergy drugs contain both a decongestant and an antihistamine. These include:1

  • Cetirizine and pseudoephedrine (Zyrtec-D® 12-hour)
  • Desloratadine and pseudoephedrine (Clarinex-D®)
  • Fexofenadine and pseudoephedrine hcl (Allegra-D®)
  • Loratadine and pseudoephedrine (Claritin-D®)

What are the possible side effects of decongestants?

Side effects can vary depending on the specific drug you are taking. The most common side effects of decongestants include:1-3

  • Insomnia (sleeping problems)
  • Headache
  • Dizziness
  • Nervousness
  • Irritability

Some people find it helpful to cut back on caffeine and to avoid using decongestants in the evening.2

Decongestants may interact with many other common drugs. Talk to your doctor about any other drugs you are taking and read the directions carefully.3

These are not all the possible side effects of decongestants. Talk to your doctor about what to expect when taking decongestants. You also should call your doctor if you have any changes that concern you when taking these drugs.

Things to know about decongestants

Oral decongestants (pills) provide longer relief but also take longer to take effect. Sprays and drops provide rapid relief.1-4

Nasal sprays provide quick relief of symptoms, but they should not be used every day. Nasal decongestants can be short- (3 to 4 hours) or long-acting (8 to 12 hours.)3

Long-term use of decongestant nasal sprays can cause rebound congestion (rhinitis medicamentosa). The rebound results in constant congestion that is a reaction to the medicine, not allergies. Nasal spray decongestants may avoid some of the side effects that may develop from those that are taken by mouth.1-3

Decongestants are not recommended for everyone. Talk to your doctor before taking a decongestant if you have:1-4

  • High blood pressure
  • Heart conditions
  • Glaucoma
  • Prostate problems
  • Thyroid problems
  • Are pregnant

Your doctor can recommend which kind of decongestant is right for you. It can be a process of trial and error to find the best one.

Before beginning treatment with decongestants, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you take. This includes over-the-counter drugs.