Phenothrin, also called sumithrin and d-phenothrin, is a synthetic

pyrethroid A pyrethroid is an organic compound similar to the natural pyrethrins, which are produced by the flowers of pyrethrums (''Chrysanthemum cinerariaefolium'' and '' C. coccineum''). Pyrethroids are used as commercial and household insecticides. I ...

that kills adult

flea Flea, the common name for the order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by ingesting the blood of their hosts. Adult fleas grow to about long, a ...

s and

tick Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...

s. It has also been used to kill

head lice The head louse (''Pediculus humanus capitis'') is an obligate ectoparasite of humans. Head lice are wingless insects that spend their entire lives on the human scalp and feeding exclusively on human blood. Humans are the only known hosts of thi ...

in humans. d-Phenothrin is used as a component of aerosol insecticides for domestic use. It is often used with

methoprene Methoprene is a juvenile hormone (JH) analog which acts as a growth regulator when used as an insecticide. It is an amber-colored liquid with a faint fruity odor. Methoprene does not kill insects. Instead, it interferes with an insect’s life ...

, an insect growth regulator that interrupts the insect's biological lifecycle by killing the eggs.

Effects

Phenothrin is primarily used to kill fleas and ticks. It is also used to kill head lice in humans, but studies conducted in Paris and the United Kingdom have shown widespread resistance to phenothrin. It is extremely toxic to bees. A

U.S. Environmental Protection Agency The Environmental Protection Agency (EPA) is an Independent agencies of the United States government, independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon pro ...

(EPA) study found that 0.07 micrograms were enough to kill

honey bee A honey bee (also spelled honeybee) is a eusocial flying insect within the genus ''Apis'' of the bee clade, all native to Afro-Eurasia. After bees spread naturally throughout Africa and Eurasia, humans became responsible for the current cosm ...

s. It is also extremely toxic to aquatic life with a study showing concentrations of 0.03 ppb killing mysid shrimp. It has increased risk of liver cancer in rats and mice in long-term exposure, with doses in the range of 100 milligrams per kilogram of body weight per day, or above. It is capable of killing

mosquitoes Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small Diptera, flies within the family Culicidae (from the Latin ''culex'' meaning "gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish ...

, although remains poisonous to cats and dogs, with seizures and deaths being reported due to poisoning. Specific data on concentrations or exposure are lacking. Phenothrin has been found to possess

antiandrogen Antiandrogens, also known as androgen antagonists or testosterone blockers, are a class of drugs that prevent androgens like testosterone and dihydrotestosterone (DHT) from mediating their biological effects in the body. They act by blocking the ...

properties, and was responsible for a small epidemic of

gynecomastia Gynecomastia (also spelled gynaecomastia) is the abnormal non-cancerous enlargement of one or both breasts in males due to the growth of breast tissue as a result of a hormone imbalance between estrogens and androgens. Updated by Brent Wisse ( ...

via isolated environmental exposure. The EPA has not assessed its effect on cancer in humans. However, one study performed by the Mount Sinai School of Medicine linked sumithrin with

breast cancer Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a r ...

; the link made by its effect on increasing the expression of a gene responsible for

mammary A mammary gland is an exocrine gland in humans and other mammals that produces milk to feed young offspring. Mammals get their name from the Latin word ''mamma'', "breast". The mammary glands are arranged in organs such as the breasts in prima ...

tissue proliferation.

EPA action

In 2005, the U.S. EPA cancelled permission to use phenothrin in several flea and tick products, at the request of the manufacturer,

Hartz Mountain Industries Hartz Mountain Industries (HMI) is a private family-owned-and-operated company known for its real estate holdings in the New York/New Jersey Metropolitan Area. Its former parent, Hartz Mountain Corporation, which is notable for its pet product ...

. The products were linked to a range of adverse reactions, including hair loss, salivation, tremors, and numerous deaths in cats and kittens. In the short term, the agreement called for new warning labels on the products. As of March 31, 2006, the sale and distribution of Hartz's phenothrin-containing flea and tick products for cats has been terminated. However, EPA's product cancellation order did not apply to Hartz flea and tick products for dogs, and Hartz continues to produce many of its flea and tick products for dogs. See also "dog" in the following EPA ruling:

References

External links

d-Phenothrin general information
–

National Pesticide Information Center The National Pesticide Information Center (NPIC) is a collaboration between Oregon State University and the United States Environmental Protection Agency to provide objective, science-based information about pesticides, the recognition and managem ...

Pyrethrins and Pyrethroids Fact Sheet – National Pesticide Information Center

* {{Human lice Chrysanthemate esters Endocrine disruptors Nonsteroidal antiandrogens Pest control (3-phenoxyphenyl)methyl 2,2,3-trimethylcyclopropane-1-carboxylates