Abstract
The pyrethrins have a long and fascinating history. They were derived from dried chrysanthemum flower heads that were found to have pesticidal activity centuries ago. They comprise a complex mixture of six main chemicals. Commercial formulations usually contain piperonyl butoxide, which inhibits metabolic degradation of the active ingredients. Pyrethrins are readily absorbed from the gut and respiratory tract but poorly absorbed through skin. The active components are rapidly and extensively metabolised in the liver. Pyrethrins probably act on sodium channels resulting in nervous system overactivity. The possibility that they also induce hypersensitivity, which may be fatal when the respiratory tract is involved, has been debated for many years. A few clinical reports support this suggestion but the limited epidemiological evidence available is against it. The number of reports of toxicity caused by pyrethrins has greatly decreased over recent years. The pyrethrins are generally of low acute toxicity but convulsions may occur if substantial amounts are ingested. Two deaths from acute asthma have been attributed to pyrethrins and clinical reports suggest that they may also cause a variety of forms of dermatitis. Ocular exposure has resulted in corneal erosions. Management of pyrethrin toxicity is supportive and symptomatic.
Similar content being viewed by others
References
Taplin D, Meinking TL. Pyrethrins and pyrethroids in dermatology. Arch Dermatol 1990; 126: 213–21
Bradberry SM, Cage SA, Proudfoot AT, et al. Poisoning due to pyrethroids. Toxicol Rev 2005; 24: 93–106
USP NF 2005: The official compendia of standards. 28/23 ed. Rockville (MD): The United States Pharmacopeial Convention, 2004
The British Pharmacopoeia Commission, editors. The British Pharmacopoeia 2004: BP (Vet). London: The Stationery Office Books, 2004
Litovitz TL, Felberg L, Soloway RA, et al. 1994 Annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System. Am J Emerg Med 1995; 13: 551–97
Litovitz TL, Klein-Schwartz W, Dyer KS, et al. 1997 Annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System. Am J Emerg Med 1998; 16: 443–97
Watson WA, Litovitz TL, Klein-Schwartz W, et al. 2003 Annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System. Am J Emerg Med 2004; 22: 335–404
Shafey O, Mehler L, Baum L. Illnesses associated with use of automatic insecticide dispenser units: selected states and United States, 1986–1999. MMWR Morb Mortal Wkly Rep 2000; 49: 492–5
Wax PM, Hoffman RS. Fatality associated with inhalation of a pyrethrin shampoo. J Toxicol Clin Toxicol 1994; 32: 457–60
Wagner SL. Fatal asthma in a child after use of an animal shampoo containing pyrethrin. West J Med 2000; 173: 86–7
Pfeil R. Pyrethrins (addendum). In: Pesticide residues in food: evaluations 2003. Part II: toxicological. Geneva: WHO/PCS, 2004: 321–8
Ray DE. Toxicology of pyrethrins and synthetic pyrethroids. In: Marrs TC, Ballantyne B, editors. Pesticide toxicology and international regulation. Chichester: John Wiley & Sons, 2004: 129–58
Narahashi T. The role of ion channels in insecticide action. In: Narahashi T, Chambers JE, editors. Insecticide action: from molecule to organism. New York: Plenum Press, 1989: 55–84
Eells JT, Bandettini PA, Holman PA, et al. Pyrethroid insecticide-induced alterations in mammalian synaptic membrane potential. J Pharmacol Exp Ther 1992; 262: 1173–81
Hodgson E, Levi PE. Interactions of piperonyl butoxide with cytochrome P450. In: Glynne Jones D, editor. Piperonyl butoxide. London: Academic Press, 1999: 41–53
Wester RC, Bucks DAW, Maibach HI. Human in vivo percutaneous absorption of pyrethrin and piperonyl butoxide. Food Chem Toxicol 1994; 32: 51–3
Chambers J. An introduction to the metabolism of pyrethroids. Residue Rev 1980; 73: 101–24
Selim S, Preiss FJ, Gabriel KL, et al. Absorption and mass balance of piperonyl butoxide following an 8-h dermal exposure in human volunteers. Toxicol Lett 1999; 107: 207–17
Kamienski FX, Casida JE. Importance of demethylenation in the metabolism in vivo and in vitro of methylenedioxyphenyl synergists and related compounds in mammals. Biochem Pharmacol 1970; 19: 91–112
Kinsler S, Levi PE, Hodgson E. Relative contributions of the cytochrome P450 and flavin-containing monooxygenases to the microsomal oxidation of phorate following treatment of mice with phenobarbital, hydrocortisone, acetone, and piperonyl butoxide. Pestic Biochem Physiol 1990; 37: 174–81
Dalvi RR, Dalvi PS. Differences in the effects of piperine and piperonyl butoxide on hepatic drug-metabolizing enzyme system in rats. Drug Chem Toxicol 1991; 14: 219–29
Conney AH, Chang R, Levin WM, et al. Effects of piperonyl butoxide on drug metabolism in rodents and man. Arch Environ Health 1972; 24: 97–107
Krieger RI, editor. Handbook of pesticide toxicology: agents. 2nd ed. San Diego (CA): Academic Press, 2001
Bosredon. Intoxication par la pudre de pyrèthre. Bull Gén Thér (Paris) 1897; 132: 275–6
Wakhlu AK, Peshin SN. Pyrethrum poisoning. J Indian Med Assoc 1969; 52: 118
Garratt JR, Bigger JW. Asthma due to insect powder. BMJ 1923; 2: 764
Paton DL, Walker JS. Pyrethrin poisoning from commercial-strength flea and tick spray. Am J Emerg Med 1988; 6: 232–5
Culver CA, Malina JJ, Talbert RL. Probable anaphylactic reaction to a pyrethrin pediculicide shampoo. Clin Pharm 1988; 7: 846–9
Newton JG, Breslin ABX. Asthmatic reactions to a commonly used aerosol insect killer. Med J Aust 1983; 1: 378–80
Carlson JE, Villaveces JW. Hypersensitivity pneumonitis due to pyrethrum: report of a case. JAMA 1977; 237: 1718–9
Ramirez MA. Pyrethrum: an etiological factor in vasomotor rhinitis and asthma. J Allergy 1930; 1: 149–55
Rickett FE, Tyszkiewicz K, Brown NC. Pyrethrum dermatitis. Part I: the allergenic properties of various extracts of pyrethrum flowers. Pyrethrum Post 1972; 11: 85
Food and Agriculture Organization/World Health Organization. Pesticide residues in food: evaluations 1999. Part II: toxicological. Geneva: WHO/PCS, 2000
McCord CP, Kilker CH, Minster DK. Pyrethrum dermatitis: a record of the occurrence of occupational dermatoses among workers in the pyrethrum industry. JAMA 1921; 77: 448–9
Mitchell JC, Dupuis G, Towers GHN. Allergic contact dermatitis from pyrethrum (Chrysanthemum spp.): the roles of pyrethrosin, a sesquiterpene lactone, and of pyrethrin II. Br J Dermatol 1972; 86: 568–73
Schnaps Y, Gross M, Trau H. Erythema multiforme due to pyrethrum. Clin Pediatr 1981; 20: 68
Pe’er J, Benezra D. Corneal damage following the use of the pediculicide A-200 pyrinate. Arch Ophthalmol 1988; 106: 16–7
Acknowledgements
No sources of funding were used to assist in the preparation of this review. The author has no conflicts of interest that are directly relevant to the contents of this review.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Proudfoot, A.T. Poisoning due to Pyrethrins. Toxicol Rev 24, 107–113 (2005). https://doi.org/10.2165/00139709-200524020-00004
Published:
Issue Date:
DOI: https://doi.org/10.2165/00139709-200524020-00004