Molecule

Drug Groups

approved

Description

An organochlorine insecticide that has been used as a pediculicide and a scabicide. Lindane has been banned in California, United Kingdom, Australia, and many western countries due to concerns about neurotoxicity and adverse effects on the environment. In Canada, Lindane is not recommmended as a first-line therapy due to reports of resistance, neurotoxicity, and bone marrow suppression, but has been approved by the FDA as a second-line therapy for topical treatment of pediculosis capitis (head lice), pediculosis pubis (pubic lice), or scabies in patients greater than two years of age who cannot tolerate or have failed first-line treatment.

Indication

For the treatment of patients infested with Sarcoptes scabiei or pediculosis capitis who have either failed to respond to adequate doses, or are intolerant of other approved therapies.

Pharmacology

Scabies is a common, highly pruritic infestation of the skin caused by Sarcoptes scabiei (lice). It is a very contagious condition with specific lesions, such as burrows, and nonspecific lesions, such as papules, vesicles and excoriations. The typical areas of the body it affects are finger webs, scalp (hair), wrists, axillary folds, abdomen, buttocks, inframammary folds and genitalia (males). It is characterized by intense night-time itching. Scabies is spread through close personal contact (relatives, sexual partners, schoolchildren, chronically ill patients and crowded communities). Scabies infestations and the corresponding symptoms can be eliminated by killing the scabies with topical insecticides or scabicides. Lindane is a scabicide that is essentially an organochloride insecticide.

Toxicity

Lindane is a moderately toxic compound via oral exposure, with a reported oral LD₅₀ of 88 to 190 mg/kg in rats. Gamma-HCH (which constitutes 99% of lindane) is generally considered to be the most acutely toxic of the isomers following single administration. It is moderately toxic via the dermal route as well, with reported dermal LD₅₀ values of 500 to 1000 mg/kg in rats, 300 mg/kg in mice, 400 mg/kg in guinea pigs, and 300 mg/kg in rabbits. Acute exposure to lindane may lead to central nervous system stimulation (usually developing within 1 hour), mental/motor impairment, excitation, clonic (intermittent) and tonic (continuous) convulsion. Other adverse reactions include central nervous system toxicity, as well as skin and gastrointestinal changes.

Affected Organisms

Biotransformation

Primarily hepatic through dechlorination leading to 2-chlorophenol, 0-chlorophenol, chlorocyclohexane, chlorocyclohexanol.

Absorption

Lindane is absorbed significantly through the skin. A mean peak blood concentration of 28 nanograms per mL occurred in infants and children 6 hours after total body application of lindane lotion for scabies.

Half Life

18 hours

Protein Binding

91%

References

External Links