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FDA alerts health care professionals of significant safety risks associated with cesium chloride

July 23,2018


Cesium chloride (CsCl) is a mineral salt that is sometimes taken either by mouth, or by injection into the body, by cancer patients who seek alternative treatments. However, no CsCl products have been approved by FDA to treat cancer or other diseases. Furthermore, animal research has shown that taking CsCl can cause irregular heartbeats, also called arrhythmias. There have been reports of humans experiencing serious heart problems after taking CsCl. CsCl is associated with a lower blood level of potassium, which is a mineral that is essential to normal heart function.1,3

FDA received a request that CsCl be moved to the category of bulk drug substances (active pharmaceutical ingredients) that present significant safety risks in compounding. FDA intends to take action, such as issue a warning letter or pursue a seizure of product or injunction, if it encounters compounding using substances placed in this category.4 FDA reviewed all adverse events related to CsCl and other cesium salts (herein referred to as “cesium”) that were reported to FDA or that were published in medical journals through June 30, 2018. FDA identified 23 reports describing serious adverse events associated with cesium, including problems with the heart.

Adverse Events

FDA identified 5 reports submitted to FDA and 18 published in the medical literature describing patients who experienced adverse events from cesium.3,6-22 Seventeen of those reports were associated with CsCl, compared to 6 with other cesium salts like cesium carbonate. Most patients took cesium to try to treat cancer. The doses described in these cases ranged from 500 milligrams taken every day to 100 grams taken over eleven days. Most reports did not identify where the cesium was obtained. In at least 8 of these cases, health care professionals measured cesium concentrations in the bodies of cesium users and found measured quantities that were several hundred to thousand-fold higher than normal.3

Reported adverse events included QT prolongation (a dangerous abnormality that can impair the heart’s ability to maintain a normal rhythm), low potassium, seizures, potentially lethal arrhythmias, fainting, cardiac arrest (the heart stopped beating), and death. QT prolongation was the most frequently reported adverse event. QT prolongation in the presence of low potassium usually improves quickly when potassium is administered, but 9 out of 11 of these patients receiving the potassium treatment either did not respond as well as expected or did not respond at all. Of the remaining 2 patients, 1 improved as expected and 1 had an unknown response. Three patients were treated with a cesium-binding agent called Prussian Blue (ferric hexacyanoferrate(II)) and had an improvement in the QT within a few days. For others, it took several weeks after the cesium was stopped for their QT prolongation to improve. This is probably because when cesium is taken on an ongoing basis, it leaves the body very gradually and may take from 6 months to 2 years to be eliminated.20

Six deaths were reported with the use of cesium. FDA considers two of these deaths to be possibly associated with cesium chloride. The reports for these two deaths described cardiac arrest or arrhythmia occurring during, or within 24 hours of injection, of cesium.19 Three reports did not describe the cause of death, and 1 person may have died from advanced cancer and bloodstream infection. However, we cannot exclude cesium as a contributing factor in these death cases. It is often difficult to use case reports to confirm that a drug caused an adverse event because the reports may exclude important details like cause of death, timing and amount of drug dose, and whether a patient was taking other medicines or had other health problems.

The three most recent medical literature reports, all published in 2018, describe patients who were taking CsCl to try to treat their advanced cancer.6, 7, 8 Two experienced life-threatening arrhythmias and cardiac arrest but were able to be resuscitated. The third had repeated seizures and loss of consciousness. All three patients had very prolonged QT intervals. These cases provide additional evidence of cesium’s ability to cause grave harm.


The use of cesium poses significant safety risks (e.g., heart toxicity) and is potentially associated with death. These events can occur with oral administration and/or injection. This raises serious concerns about its use in compounding. Therefore, FDA has decided to move CsCl to the category of substances that present significant safety risks in compounding. Consumers, patients, and health care professionals should be aware of the significant potential health risks from cesium. FDA encourages consumers, patients, and health care professionals to report adverse events or quality problems experienced with the use of compounded drug products to FDA’s MedWatch Adverse Event Reporting program:


  1. Cesium. Natural Medicines Database website. https://naturalmedicines.therapeuticresearch.com/databases/food,-herbs-supplements/professional.aspx?productid=1064. Updated 11/30/2017. Accessed 7/12/2018.
  2. Mohsen Nayebpour, B Charles Solymoss, Stanley Nattel. Cardiovascular and metabolic effects of caesium chloride injection in dogs — limitations as a model for the long QT syndrome, Cardiovascular Research. 1989;23(9):756–66. https://doi.org/10.1093/cvr/23.9.756
  3. Horn S, Naidus E, Alper SL, Danziger J. Cesium-associated hypokalemia successfully treated with amiloride. Clin Kidney J. 2015;8:335–8 doi:10.1093/ckj/sfv017.
  4. Interim Policy on Compounding Using Bulk Drug Substances Under Section 503A of the Federal Food, Drug, and Cosmetic Act. January 2017. https://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/UCM469120.pdf Accessed 7/13/2018.
  5. Patel, P.R., Rathod, J.. “Life threatening neurologic and cardiac toxicity due to cesium chloride used for the holistic treatment,” Am J Respir Crit Care Med, 2018:197:A6906.
  6. Rodriguez, F.F., Liroff, K.G., “Cesium chloride: Prolonging QTC intervals, not life expectancy,” J of Gen Int Med, 2018:33;490.
  7. Mahida H., Maludum O., Ugoeke N., Gharia B., Calderon D., Litsky J., Patel A., “Cesium induced acquired long QT syndrome leading to torsades de pointes”, Journal of the American College of Cardiology, 2018:71 (11); A2612.
  8. Saliba W, Erdogan O, Niebauer M. Polymorphic ventricular tachycardia in a woman taking cesium chloride. Pacing Clin Electrophysiol. 2001;24(4 Pt 1):515-7.
  9. Pinter A, Dorian P, Newman D. Cesium-induced torsades de pointes. N Engl J Med. 2002;346(5):383-4.
  10. Lyon AW, Mayhew WJ. Cesium toxicity: a case of self-treatment by alternate therapy gone awry. Ther Drug Monit. 2003;25(1):114-6.
  11. Centeno JA, Pestaner J, Omalu B, Torres N, Field F, Wagner G, et al. Blood and tissue concentration of cesium after exposure to cesium chloride: a report of two cases. Biol Trace Elem Res. 2003;94(2):97-104.
  12. Dalal AK, Harding JD, Verdino RJ. Acquired long QT syndrome and monomorphic ventricular tachycardia after alternative treatment with cesium chloride for brain cancer. Mayo Clin Proc. 2004;79(8):1065-9. Erratum in: Mayo Clin Proc. 2004;79(9):1215.
  13. Curry TB, Gaver R, White RD. Acquired long QT syndrome and elective anesthesia in children. Paediatr Anaesth. 2006;16(4):471-8.
  14. Vyas H, Johnson K, Houlihan R, Bauer BA, Ackerman MJ. Acquired long QT syndrome secondary to cesium chloride supplement. J Altern Complement Med. 2006;12(10):1011-4.
  15. O'Brien CE, Harik N, James LP, Seib PM, Stowe CD. Cesium-induced QT-interval prolongation in an adolescent. Pharmacotherapy. 2008;28(8):1059-65. doi: 10.1592/phco.28.8.1059.
  16. Chan CK, Chan MH, Tse ML, Chan IH, Cheung RC, Lam CW, Lau FL.Life-threatening Torsades de Pointes resulting from "natural" cancer treatment. Clin Toxicol (Phila). 2009; 47(6):592-4.
  17. Wiens M, Gordon W, Baulcomb D, Mattman A, Mock T, Brown R. Cesium chloride-induced torsades de pointes. Can J Cardiol. 2009;25(9):e329-31.
  18. Sessions D, Heard K, Kosnett M. Fatal cesium chloride toxicity after alternative cancer treatment. J Altern Complement Med. 2013;19(12):973-5.
  19. Young F, Bolt J. Torsades de pointes-a report of a case induced by caesium taken as a complementary medicine, and the literature review. J Clin Pharm Ther. 2013; 38:254-7.
  20. Khangure SR, Williams E, Welman C. CT brain findings in a patient with elevated brain cesium levels. Neuroradiol J. 2013;26(6):607-9. Epub 2013 Dec 18.
  21. Warsame MO, Gamboa D, Nielsen EW. [A woman in her forties with cancer, syncope and spasms]. Tidsskr Nor Laegeforen. 2014;134(19):1855-7.
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