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Toxicity, Fluoride

Author: Geofrey Nochimson, MD, Consulting Staff, Department of Emergency Medicine, Sentara Careplex Hospital
Contributor Information and Disclosures

Updated: Dec 2, 2008

Introduction

Background

Fluoride toxicity is characterized by a variety of signs and symptoms. Poisoning most commonly occurs following ingestion (accidental or intentional) of fluoride-containing products. Symptom onset usually occurs within minutes of exposure.

Fluoride is found in many common household products, including toothpaste (eg, sodium monofluorophosphate), vitamins, dietary supplements (eg, sodium fluoride), glass-etching or chrome-cleaning agents (eg, ammonium bifluoride), and insecticides and rodenticides (eg, sodium fluoride). Historically, most cases of fluoride toxicity have followed accidental ingestion of insecticides or rodenticides.

Pathophysiology

Fluoride has several mechanisms of toxicity. Ingested fluoride initially acts locally on the intestinal mucosa. It can form hydrofluoric acid in the stomach, which leads to GI irritation or corrosive effects. Following ingestion, the GI tract is the earliest and most commonly affected organ system.

Once absorbed, fluoride binds calcium ions and may lead to hypocalcemia. Fluoride has direct cytotoxic effects and interferes with a number of enzyme systems; it disrupts oxidative phosphorylation, glycolysis, coagulation, and neurotransmission (by binding calcium). Fluoride inhibits Na+/K+ -ATPase, which may lead to hyperkalemia by extracellular release of potassium. Fluoride inhibits acetylcholinesterase, which may be partly responsible for hypersalivation, vomiting, and diarrhea (cholinergic signs). Seizures may result from both hypomagnesemia and hypocalcemia. Severe fluoride toxicity will result in multiorgan failure. Central vasomotor depression as well as direct cardiotoxicity also may occur. Death usually results from respiratory paralysis, dysrhythmia, or cardiac failure.

Frequency

United States

In 2006, the American Association of Poison Control Centers reported 22,168 exposures involving toothpaste with fluoride.1

Only 313 cases were actually treated in the emergency department. Moderate effects were seen in 45 cases. No cases of major adverse effects or death were reported.1

In 2006, 1802 exposures involving multiple vitamins with fluoride were reported.1

Only 61 cases were treated in the emergency department with no moderate or major effects noted.1

Mortality/Morbidity

One death from ingestion of fluoride toothpaste was reported to the American Association of Poison Control Centers in 2002.

No deaths were reported in 2006.1

  • Death may result from ingesting as little as 2 g of fluoride in an adult and 16 mg/kg in children. Symptoms may appear with 3-5 mg/kg of fluoride.
  • Estimated toxic dose for fluoride ingestion is 5-10 mg/kg.
  • Estimated lethal dose is 5-10 g (32-64 mg/kg) in adults and 500 mg in small children.

Age

Children younger than 6 years account for the vast majority of the cases. In 2006, this age group had a total 21,064 exposures, while adults 19 years and older had only 982 exposures.1

  • Infants and children usually have accidental exposures.
  • Adults usually have intentional exposures.

Clinical

History

  • Determine the exact nature and time of exposure or ingestion. Query patient, bystanders, paramedics, and family members regarding specifics of exposure or ingestion.

Physical

  • Gastrointestinal signs predominate
    • Hypersalivation
    • Nausea
    • Vomiting
    • Diarrhea
    • Abdominal pain
    • Dysphagia
    • Mucosal injury
  • Electrolyte abnormalities
  • Neurologic effects
    • Headache
    • Tremors
    • Muscular spasm
    • Tetanic contractions
    • Hyperactive reflexes
    • Seizures
    • Muscle weakness
  • Cardiovascular
    • Widening of QRS
    • Various arrhythmias
    • Shock
    • Cardiac arrest

Causes

  • The most common type of exposure is ingestion of products that contain fluoride. To obtain the exact name of the product and how much was ingested is extremely important.
  • Toothpaste contains 1 mg/g of fluoride as sodium monofluorophosphate. This fluoride formulation has low solubility and is generally nontoxic.
  • The toxic effects following large ingestions of the following products usually are limited to GI discomfort.
    • Toothpaste
    • Oral hygiene products
    • Insecticide
    • Rodenticide
    • Dietary supplements
    • Automobile wheel-cleaning products
    • Glass-etching products

More on Toxicity, Fluoride

Overview: Toxicity, Fluoride
Differential Diagnoses & Workup: Toxicity, Fluoride
Treatment & Medication: Toxicity, Fluoride
Follow-up: Toxicity, Fluoride
References
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References

  1. Bronstein AC, Spyker DA, Cantilena LR Jr, Green J, Rumack BH, Heard SE. 2006 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS). Clin Toxicol (Phila). Dec 2007;45(8):815-917. [Medline]. [Full Text].

  2. Augenstein WL, Spoerke DG, Kulig KW, et al. Fluoride ingestion in children: a review of 87 cases. Pediatrics. Nov 1991;88(5):907-12. [Medline].

  3. Eichler HG, Lenz K, Fuhrmann M, Hruby K. Accidental ingestion of NaF tablets by children--report of a poison control center and one case. Int J Clin Pharmacol Ther Toxicol. Jul 1982;20(7):334-8. [Medline].

  4. Gessner BD, Beller M, Middaugh JP, Whitford GM. Acute fluoride poisoning from a public water system. N Engl J Med. Jan 13 1994;330(2):95-9. [Medline].

  5. Kao WF, Deng JF, Chiang SC. A simple, safe, and efficient way to treat severe fluoride poisoning--oral calcium or magnesium. J Toxicol Clin Toxicol. 2004;42(1):33-40. [Medline].

  6. Klasaer AE, Scalzo AJ, Blume C, et al. Marked hypocalcemia and ventricular fibrillation in two pediatric patients exposed to a fluoride-containing wheel cleaner. Ann Emerg Med. Dec 1996;28(6):713-8. [Medline].

  7. McIvor ME. Acute fluoride toxicity. Pathophysiology and management. Drug Saf. Mar-Apr 1990;5(2):79-85. [Medline].

  8. Schneir A, Clark RF, Kene M, Betten D. Systemic fluoride poisoning and death from inhalational exposure to sulfuryl fluoride. Clin Toxicol (Phila). Jun 16 2008;1-5. [Medline].

  9. Shulman JD, Wells LM. Acute fluoride toxicity from ingesting home-use dental products in children, birth to 6 years of age. J Public Health Dent. Summer 1997;57(3):150-8. [Medline].

  10. Vance M. Fluoride poisoning. In: The Clinical Process of Emergency Medicine. Vol 1. 1991:507-9.

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Further Reading

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Keywords

fluoride poisoning, fluoride toxicity, fluoride ingestion, toothpaste, sodium monofluorophosphate, dietary supplement, sodium fluoride, glass-etching agent, chrome-cleaning agent, ammonium bifluoride, insecticide, rodenticide 

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Contributor Information and Disclosures

Author

Geofrey Nochimson, MD, Consulting Staff, Department of Emergency Medicine, Sentara Careplex Hospital
Geofrey Nochimson, MD is a member of the following medical societies: American College of Emergency Physicians
Disclosure: Nothing to disclose.

Medical Editor

David C Lee, MD, Research Director, Department of Emergency Medicine, Assistant Professor, North Shore University Hospital and New York University Medical School
David C Lee, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American College of Medical Toxicology, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Pharmacy Editor

John T VanDeVoort, PharmD, ABAT, Director of Pharmacy, Sacred Heart Hospital
John T VanDeVoort, PharmD, ABAT is a member of the following medical societies: American Academy of Clinical Toxicology and American Society of Health-System Pharmacists
Disclosure: Nothing to disclose.

Managing Editor

Michael J Burns, MD, Instructor, Department of Emergency Medicine, Harvard University Medical School, Beth Israel Deaconess Medical Center
Michael J Burns, MD is a member of the following medical societies: American Academy of Clinical Toxicology, American College of Emergency Physicians, American College of Medical Toxicology, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Asim Tarabar, MD, Assistant Professor, Department of Surgery, Section of Emergency Medicine, Yale University School of Medicine; Consulting Staff, Department of Emergency Medicine, Yale-New Haven Hospital
Disclosure: Nothing to disclose.

 
 
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