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Clinical Pharmacology "Adverse Drug
Event of the month"
Laxman Rekha (Permethrin) poisoning in children - Cases admitted to KEM hospital and review of literature Introduction and cases During an intensive in hospital adverse event monitoring in the department of pediatrics at KEM hospital, 2 cases with alleged history of insecticide ingestion (Laxman Rekha-a commonly used household insecticide, containing permethrin) were admitted in the month of February and March. Both were male 1year and 2 years old respectively. Both had accidentally ingested 2-3 pieces of insecticide bar. They had history of vomiting with ingested pieces present in the vomitus. There was no history of rash, diarrhoea, headache, tinnitus, tremors, in-coordination or muscular paralysis. Vital parameters were stable at the time of admission. Stomach wash and other symptomatic treatment was given. Patients were kept under observation for 2 days. They were discharged from the hospital after an uneventful hospital stay of 48 hours. Discussion: Laxman Rekha is a commonly used household insecticide recommended by the manufacturer for use against cockroaches .It is available in the form of solid green chalk and contains permethrin as the main constituent. (Composition is 1% cypermethrin and 99% adjuvant) Permethrin is synthetic pyrethroid obtained from flowers of Chrysanthemum Cinerariifolium. These flowers are cultured in Shimla and Kashmir in India and contain pyrethrin and cinnerin as active principles. Permethrin was first chemically synthesized in 1973. It acts as a contact poison for insects like mosquitoes, flies, ticks, and chiggers. It affects nervous system of insects by blocking sodium channels in the nerve membrane and causing prolongation of the transient increase in sodium permeability associated with membrane depolarization (1). In recent years synthetic pyrethroids have emerged as a potentially very useful class of insecticides with a high insect/mammal toxicity ratio, rapid detoxication in mammals and lack of cumulative toxicity (2). The oral and intravenous LD 50 values in rats are 1500 and >270mg.kg-1 respectively(1).The selective toxicity of pyrethroids to insects as compared to mammals appears to be largely due to their rapid biotranformation in mammals by way of ester hydrolysis and/or aromatic and methyl hydroxylation(2). In humans permethrin is used as local applicant for pediculosis (1% dermal cream) and scabies (5% dermal cream) and as a mosquito repellant. When used as a mosquito repellant it should be applied directly to clothing or other fabrics (such as tent walls or mosquito nets) and not to the skin. The spray form is nonstaining, nearly odorless and resistant to degradation by heat or sun and maintains its potency for at least two weeks even through several launderings. The combination of permethrin treated clothing and skin application of DEET based insect repellent creates a formidable barrier against mosquito bites (3) Permethrin toxicity can result from dermal exposure, inhalation or ingestion of products containing it. A study of childhood poisoning done at National Poison Information Center, Delhi showed that incidence of poisoning was highest (47%) due to household products comprising mainly pyrethroids, rodenticides, phenyl, detergents etc (4). Contact dermatitis with mild erythematous vesicular lesions and papules has occasionally been reported use of local applications containing permethrin (1). As a pesticide permethrin is mainly used in aerosol form. Inhalation of toxic doses of permethrin can cause allergic rhinitis, itching and sneezing, asthma, and allergic alveolitis (5). Cypermethrin (permethrin containing cyano group) can occasionally cause parasthesia (secondary to sodium channel blockade in sensory nerves), nausea, vomiting, dizziness, fasciculations, altered mental status, coma, seizure and pulmonary edema (6). Ingestion of permethrin can rarely cause similar symptoms (7). However data on toxicity after oral ingestion in humans is meager. The death of a 2-year-old child following ingestion of 14 grams of "insect powder" was attributed to permethrin (2). Treatment of permethrin poisoning is palliative and conservative. No antidote is available. Conservative treatment includes through washing of exposed skin, gastric lavage with potassium permanganate, oxygen administration, treatment of convulsions, and ventilatory support in case of respiratory failure. Taking proper precautions can prevent insecticide poisoning. Person handling should use gloves, make use of protective gear while spraying and in houses people should either vacate the room or wear masks (6). Both cases presented in this paper had accidentally ingested permethrin in the form of Laxman Rekha. It is used by drawing a line with this chalk mainly along walls, corners, bathrooms and drainage areas of washbasins in the house which makes it easily accessible to children. Both cases belonged to lower socioeconomic class where the families lived in tiny overcrowded dwellings. Etiological factors for such accidental poisoning in this age group include child's inquisitive nature, increased mobility, low socioeconomic status, lack of parental awareness, unsafe environment and accessibility to dangerous substances. Accidents and poisoning in children are eminently preventable. Poisonous products like Laxman Rekha should be kept out of the reach of children. Parents need to be informed about such dangers. Immunization visits at 9 months, monthly visits for growth monitoring and unscheduled visits for trivial childhood illnesses offer opportunities for the health care providers to educate parents. Offering advice at right time and increased parental awareness can help in reducing incidence of such absolutely preventable adverse events. References: 1. In: Dollery C, BoobisA, Rawlins M, Thomas S, Wilkins M (Eds) Therapeutic Drugs, 2nd Edition.UK: Churchill Livingston Company, 1999, Pp 56-57. 2. Murphy S D: Toxic Effects Of Pesticides. In: Claassen C D, Amdur M O, Doull J (Eds) Casarelt and daull's Toxicology.The Basic Science Of Poisons, 3rd edition. New York: MacMillan Publishing Company, 1986, Pp 519-581. 3. Mark S, Fradin M D. Mosquitoes and mosquito repellents: A clinician's guide. Ann Int Med 1998; 128:931-940 4. Gupta S K, Peshin S S, Shrivastava A, KalekalT.A study of childhood poisoning at National Poison Information Centre, All India Institute Of Medical Sciences, New Delhi. J.Occup.Health 2003; 5:191-196 5. Plunkette E R (Ed) Handbook Of Toxicology, 3rd edition. USA: Chemical Publishing Co.Inc. 1987,Pp467. 6. Howlad M A. Insecticides: Chlorinate Hydrocarbons, Pyrethrins and DEEt.In: Golgfrank LR, Flomenbaun N E, Lewin N A, Weisman R S, Howland M A, Hoffman R S (Eds) Goldfrank's Toxicologic Emergencies,6th edition USA:Applenton and Large,1998,Pp 1451-1459. 7. In: Singh U K, Layland F C, Suman S, Prasad R, (Eds) Poisoning in children 2nd edition India: Jaypee brothers.1998, Pp90-98 Department of Clinical Pharmacology* Department of Pediatrics** Seth GS Medical College and KEM hospital Parel, Mumbai 400 012, INDIA |