Tetrahydrozoline is a form of a medicine called imidazoline, which is found in over-the-counter eye drops and nasal sprays. Tetrahydrozoline poisoning occurs when someone accidentally or intentionally swallows this product.
This article is for information only. DO NOT use it to treat or manage an actual poison exposure. If you or someone you are with has an exposure, call the local emergency number (such as 911), or the local poison center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States.
Tetrahydrozoline is sold under the following brand names:
- Murine Tears Plus
- Optigene 3
- Visine Original and Advanced Relief
Note: This list may not be all inclusive.
While poisoning symptoms are uncommon after applying the drops to the eyes, these agents can produce significant poisoning if taken orally.
Symptoms may include:
- Altered mental state
- Coma (lack of responsiveness)
- Difficulty breathing or no breathing
- Blurred vision
- Blue lips and fingernails
- Changes in blood pressure (high at first, low later)
- Change in pupil size
- Fast or slow heartbeat
- Low body temperature
- Nausea and vomiting
- Nervousness, tremors
Seek medical help right away. DO NOT make a person throw up unless told to do so by poison control or a health care professional.
Before Calling Emergency
The following information is helpful for emergency assistance:
- The patient's age, weight, and condition
- The name of the product (ingredients and strengths if known)
- The time it was swallowed
- The amount swallowed
However, DO NOT delay calling for help if this information is not immediately available.
Your local poison control center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States. This national hotline will let you talk to experts in poisoning. They will give you further instructions.
This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.
Take the container with you to the hospital, if possible.
What to Expect at the Emergency Room
The health care provider will measure and monitor the person's vital signs, including temperature, pulse, breathing rate, and blood pressure. Symptoms will be treated as appropriate. The person may receive:
- Activated charcoal
- Airway support, including oxygen, breathing tube through the mouth (intubation), and ventilator (breathing machine)
- Blood and urine tests
- Chest x-ray
- ECG (electrocardiogram, or heart tracing)
- Fluids through the vein (intravenous or IV)
- Medicines to treat symptoms
Survival past 24 hours is usually a good sign that the person will recover. Some individuals may have long-lasting complications if multiple organs are damaged by the drug.
Products containing tetrahydrozoline can interact with many prescription drugs. Always read the label before using any over-the-counter (OTC) product.
In young children, serious adverse events can occur from ingesting only a small amount (1 to 2 mL, or several drops) of tetrahydrozoline. Many of these types of OTC products do not have child-resistant closures, so they should be stored out of the reach of children.
Tetryzoline; Murine; Visine
Aronson JK. Tetryzoline. In: Aronson JK, ed. Meyler's Side Effects of Drugs. 16th ed. Waltham, MA: Elsevier; 2016:793.
Yin S. Over-the-counter cough and cold preparations: Approach to pediatric poisoning. In: Burns MM, ed. UpToDate. Topic 16258 Version 15.0, November 2020.
Review Date 1/1/2021
Updated by: Jacob L. Heller, MD, MHA, Emergency Medicine, Emeritus, Virginia Mason Medical Center, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.