What Thyroid Patients Need to Know About Decongestants

Certain cold and flu drugs can pose risks if you have thyroid disease

Table of Contents
View All
Table of Contents

Decongestants can pose a risk to people living with a thyroid disorder, such as an overactive thyroid (hyperthyroidism) or an underactive thyroid (hypothyroidism).

This is because ingredients like pseudoephedrine can affect the blood vessels throughout the body. Some drugs may interact with your thyroid medication. And while there are many over-the-counter (OTC) drugs available for treating nasal congestion caused by a cold or seasonal flu, some can do more harm than good.

This article explains why some decongestants should be avoided and why it's important to discuss medication use with your healthcare provider before taking them.

cold and flu medication with thyroid disease

Verywell / Emily Roberts

Decongestants and Heart Health

Several types of decongestants work by causing the blood vessels in the linings of the nasal passages to contract and narrow. This decreases blood flow to the lining of the nose and sinuses, thereby reducing congestion and the production of mucus.

The catch is, this effect isn't limited to nasal passages: Blood vessels throughout the body are affected, which can be dangerous for someone with a thyroid condition. That's because both hyperthyroidism and hypothyroidism can affect the heart and circulatory system.

Pseudoephedrine can strain an already overtaxed heart or further increase high blood pressure, worsening two common issues related to hyperthyroidism. 

The decongestant most likely to be problematic is pseudoephedrine, which is sold not only as a single-ingredient medication, but is found in multi-symptom cold, flu, and allergy remedies as well. (Note that because pseudoephedrine has been used illegally to make methamphetamine, it is sold from behind the pharmacy counter.)

Less potentially problematic, but still important to be aware of, is phenylephrine.

These decongestants show up in many products, and some brands have products that contain both ingredients. It's important to read labels so that you know what you're taking.

These lists represent a small sample of the many OTC medications that have pseudoephedrine or phenylephrine, alone or in combination with other ingredients.

Common Medications With Psuedoephedrine
  • Advil Cold and Sinus

  • Alavert Allergy and Sinus D-12

  • Aleve-D Sinus and Cold

  • Allegra-D

  • Claritin-D

  • Mucinex D

  • Sudafed 12/24 Hour

  • Sudafed Congestion

  • Theraflu Max-D Severe Cold and Flu

  • Tylenol Sinus Severe Congestion Daytime

Common Medications With Phenylephrine
  • Actifed Cold and Allergy

  • Advil Congestion Relief

  • Alka-Seltzer Plus

  • Benedryl-D Allergy Plus Sinus

  • Excedrin Sinus Headache

  • Robitussin Cough and Cold CF

  • Sudafed PE

  • Theraflu

  • Triaminic

  • Tylenol Allergy Multisymptom

  • Vicks DayQuil

Phenylephrine is also the active ingredient in nasal sprays for treating decongestion. Although the drug is targeted to blood vessels in the lining of the nose, experts don't know for sure that it won't affect vessels throughout the body.

You should check with your healthcare provider before using a nasal spray (such as Neo-Synephrine) if you have hyperthyroidism. The same may be true for nasal sprays containing oxymetazoline. These include:

  • Afrin
  • Anefrin
  • Dristan
  • Mucinex
  • Nostrilla
  • Vicks Sinex
  • Zicam

Interactions With Thyroid Medications

Hypothyroidism is managed with a synthetic form of thyroxine (T4) called levothyroxine, available under the brand names Synthroid or Levothroid.

People may be at increased risk of cardiovascular side effects if they take pseudoephedrine or phenylephrine and levothyroxine. This could be especially dangerous for someone who has preexisting heart disease.

Regardless of the type of thyroid disorder you have, whether you take medication to treat it, or happen to have a heart condition as well, it's best to err on the side of caution before taking a decongestant for a cold or flu and speak with your healthcare provider.

Alternatives to Decongestants

People living with a thyroid condition have options to relieve nasal congestion from a cold or flu without medication. You can:

  • Try a nasal dilator that widens nasal passages, such as Breathe Right strips
  • Rinse your sinuses with a sterile saline solution (using a neti pot)
  • Use a saline spray or drops to thin mucus and make it easier to expel when you blow your nose
  • Run a humidifier in the room where you spend the most time
  • Take a warm shower or sit in the bathroom with the shower running hot enough to steam up the room
  • Try herbal remedies, including lemon grass or rosemary

Acupuncture and acupressure may also help to relieve congestion.

If none of these strategies work, check with your healthcare provider to find out if there are other ways to get relief.


Some decongestants can pose a risk to people living with certain health conditions, including a thyroid disorder. This is because ingredients in over-the-counter (OTC) products, like pseudoephedrine, can affect the heart and blood vessels. Some products also may interact with your thyroid drugs.

Be sure to discuss the use of any OTC medication with your healthcare provider before you try them. You also may wish to consider natural remedies, like using a humidifier, before you try a nasal decongestant drug.

7 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.
  1. Abdullah B, Abdul Latiff AH, Manuel AM, Mohamed Jamli F, Dalip Singh HS, Ismail IH, et al. Pharmacological Management of Allergic Rhinitis: A Consensus Statement from the Malaysian Society of Allergy and Immunology. J Asthma Allergy. 2022 Aug 2;15:983-1003. doi:10.2147/JAA.S374346.

  2. Harvard Medical School Harvard Health Publishing. Don't let decongestants squeeze your heart.

  3. Razvi S, Jabbar A, Pingitore A, et al. Thyroid hormones and cardiovascular function and diseases. Journal of the American College of Cardiology. 2018;71(16):1781-1796. doi:10.1016/j.jacc.2018.02.045

  4. Sur DK, Plesa ML. Treatment of allergic rhinitis. American Family Physician. 2015;92(11):985-92. 

  5. MedlinePlus. Oxymetazoline nasal spray.

  6. Sharma M, Gupta A, Prasad R. A review on herbs, spices and functional food used in diseases. International Journal of Research and Review. 2017; 4(1):103-108. 

  7. Lei RL, Lin WC, Lin CC, et.al. Effects of Acupressure on Symptoms Relief and Improving Sleep Quality in Pediatric Patients With Allergic Rhinitis.[published online ahead of print, 2020 Apr 1]. Holist Nurs Pract. 2020;10.1097/HNP.0000000000000377. doi:10.1097/HNP.0000000000000377

By Mary Shomon
Mary Shomon is a writer and hormonal health and thyroid advocate. She is the author of "The Thyroid Diet Revolution."