Definition

Merthiolate is a mercury-containing substance that was once widely used as germ-killer and a preservative in many different products, including vaccines.

Merthiolate poisoning occurs when large amounts of the substance are swallowed or come in contact with your skin. Poisoning may also occur if you are exposed to small amounts of merthiolate constantly over a long period of time.

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 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.

Poisonous Ingredient

Thimerosal

Where Found

Merthiolate is found in:

• Merthiolate
• Some eye drops
• Some nasal drops

The FDA banned the use of merthiolate in over-the-counter products in the late 1990s.

Symptoms

Symptoms of merthiolate poisoning include:

• Abdominal pain
• Diarrhea
• Decreased urine output
• Drooling
• Extreme difficulty breathing
• Metallic taste
• Memory problems
• Mouth sores
• Seizures
• Shock
• Skin numbness
• Swelling in the throat, which may be severe
• Thirst
• Walking problems
• Vomiting, sometimes bloody

Home Care

If you are concerned about a possible overdose, contact your local poison control center (1-800-222-1222 - United States) for advice.

Before Calling Emergency

The following information is helpful for emergency assistance:

• Person's age, weight, and condition
• Name of the product (ingredients and strength, if known)
• Time it was swallowed
• Amount swallowed

However, DO NOT delay calling for help if this information is not immediately available.

Poison Control

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.

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:

• Airway support, including oxygen, breathing tube through the mouth (intubation), and breathing machine (ventilator)
• Blood and urine tests
• Camera down the throat (endoscopy) to see burns in the food pipe (esophagus) and stomach
• Chest x-ray
• ECG (electrocardiogram, or heart tracing)
• Fluids through a vein (intravenous or IV)
• Medicines to treat symptoms, including chelators, which remove mercury from the bloodstream and may reduce long-term injury

Outlook (Prognosis)

Merthiolate poisoning is difficult to treat. How well a person does depends on the amount of poison swallowed and how quickly treatment was received. The faster a person gets medical help, the better the chance for recovery. Kidney dialysis (filtration) through a machine may be needed if the kidneys do not recover after acute mercury poisoning, Kidney failure and death can occur, even with small doses.

References

Aronson JK. Mercury and mercurial salts. In: Aronson JK, ed. Meyler's Side Effects of Drugs. 16th ed. Waltham, MA: Elsevier; 2016:844-852.

National Library of Medicine: National Center for Biotechnology Information website. Thimerosal: PubChem compound summary for CID 16684434. pubchem.ncbi.nlm.nih.gov/compound/Thimerosal. Accessed March 3, 2023.