Lindane
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Lindane
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| Systematic (IUPAC) name | |
| 1,2,3,4,5,6-hexachlorocyclohexane | |
| Identifiers | |
| CAS number | 58-89-9 |
| ATC code | P03AB02 |
| PubChem | 727 |
| DrugBank | APRD01072 |
| Chemical data | |
| Formula | C6H6Cl6 |
| Mol. weight | 290.828 g/mol |
| Pharmacokinetic data | |
| Bioavailability | ? |
| Protein binding | 91% |
| Metabolism | ? |
| Half life | 18 hours |
| Excretion | ? |
| Therapeutic considerations | |
| Pregnancy cat. |
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| Legal status | |
| Routes | ? |
Lindane is an insecticide, also known as gamma-hexachlorocyclohexane (HCH) and benzene hexachloride (BHC). It has an LD50 of 88 mg/kg, is suspected of being a carcinogen and is banned in the U.S., the state of California and in 52 countries. Larger than the issue of toxicity of Lindane itself, the ban had more to do with the other isomers of HCH produced as by-products, which had little or no use. These isomers were stockpiled in open heaps by lindane producers in the 40's and 50's leading to severe ground and water contamination. There is also a bill in the New York State Assembly and Senate to ban the use of lindane for headlice and limit its use on scabies.
Its method of action is via interfering with the GABAa receptor/Cl- channel. It is volatile with roughly 90% entering the atmosphere and ultimately being deposited in rain. In 1992 5.5 mg/L of lindane was detected in rain in Oxfordshire.[citation needed] It is still widely used in most of Europe and nearly all developing countries. Mexico is the next of many nations who are banning lindane. The EPA has banned lindane for agricultural use in the United States. Like other agricultural pesticides, lindane is very easily introduced into the water and food supply of an area through rainfall; this can lead to low-level lindane poisoning amongst the local community. A chief symptom of this is a tic causing occasional flickering of the eyelid; other than this minor discomfort, such levels of poisoning are not harmful. Lindane has caused seizures, blood disorders, brain cancer in children, and is linked to both breast cancer, and movement disorders such as Tourette's Syndrome and Parkinson's disease. Lindane is no longer manufactured in the US, but is sold as a pharmaceutical by Alliant, who sells pediatric medications, even though lindane is to be used with extreme caution in anyone under 110 pounds.
Increased Risk in Younger and/or Smaller Patients and the Elderly
Lindane is contraindicated for use in neonates and should be used with extreme caution in children and in individuals weighing less than 50 kg (110 lbs). Among adverse event reports in which the outcome was serious (resulted in hospitalization, disability or death), the very young and the elderly appeared to be more susceptible to Lindane’s adverse effects and had worse outcomes.
Animal studies have demonstrated that younger animals are more susceptible to the neurologic side effects seen with Lindane use. In addition, smaller children have a larger body surface to volume ratio that may result in proportionately larger risk of systemic exposure. For this reason, Lindane has long been contraindicated for use in neonates. It is not known whether the developing nervous system of children also increases their susceptibility to neurologic toxicity.
Other Populations with Increased Risk
Patients who have conditions, such as HIV infection, or take certain medications that may lower the seizure threshold should be prescribed Lindane with caution. They may be at greater risk for serious adverse events. The new Lindane label lists examples of some of these conditions and medications. The label also highlights special precautions for use of Lindane in women who are breastfeeding infants.
There are case reports of neurologic adverse events in nursing home patients treated with Lindane. Factors that may have increased their susceptibility to these adverse events include concomitant medications, underlying medical conditions, and advanced age. Special consideration should be given prior to treating this population with Lindane, even if they are greater than 50 kg.
It is sold in a one-percent formulation as Kwell shampoo and lotion (among other brand names, also generically), used to treat human scabies infection, head lice and other ectoparasites. It has recently been banned for the treatment of head lice in California. In the United States, the Food and Drug Administration requires these products be labeled with prominent warnings about possible neurotoxicity, particularly in young patients. Even though the FDA has blackboxed lindane, it is still being prescribed for children and the elderly, whose skin is more permeable and vulnerable to its toxic effects. Medicaid, Medicare, and many state-funded health care systems still have lindane on their formularies, when there are many safer and more effective treatments available. Alliant Pharmaceuticals only sells lindane in 2 oz bottles which is an amount for a large adult, when the FDA states it is to be sold in one and two ounce bottles, so children are STILL given a very high dosage of lindane which is the least effective and most toxic of all headlice treatments. Scientists report that lindane is currently among the least effective means to control lice and scabies. In a recent article, researchers studying the effectiveness of lindane for lice control "strongly recommend its removal from the market." In an informal survey conducted by the California chapter of the American Academy for Pediatrics, doctors report that they had stopped using lindane even before the California ban because of "low efficacy and high toxicity." PANNA
Lindane has little if any role in the treatment of head lice. Studies have documented its poor pediculicidal and ovicidal activity, and it is potential neurotoxicity by Edward A. Bell, PharmD, BCPS Special to Infectious Diseases in Children
Lindane also had the slowest pediculicidal and least effective ovicidal activity compared with three other approved pediculicides (i.e., 1% permethrin, 0.3% pyrethrin, and 0.5% malathion)Centers for Disease Control and Prevention
6. Isn’’t 1% Lindane that the doctor prescribes the most effective? No. Lindane is no longer the drug of choice. It may be that lice are becoming resistant to this product. Recent studies show that 1% Lindane (i.e., Quell®®, Scabbing®®) is the least effective at killing lice. SONOMA COUNTY HEALTH DEPARTMENT SERVICES
The International HCH and Pesticides Association (IHPA) was founded in July 1998 with the aim of facilitating and promoting international co-operation and the exchange of experiences within management of pollution problems stemming from the production and use of HCH and other unwanted pesticides worldwide. Since September 2002, the IHPA has been officially registered as a Foundation in The Netherlands.
The IHPA supports the work towards sustainable solutions in production and application of pesticides and promotes international co-operation of all parties involved in the field of pesticides.
[edit] References
- This article is based in part on the public domain US government document at [1].
