Class: Scabicides and Pediculicides
VA Class: AP300
Chemical Name: [(Dimethoxyphosphinothioyl)-thio]-butanedioic acid diethyl ester
Molecular Formula: C10H19O6PS2
CAS Number: 121-75-5
Pediculicide; organophosphate anticholinesterase insecticide.1
Uses for Malathion
Base selection of a pediculicide on efficacy (including both pediculicidal and ovicidal activity), safety, cost, availability, ease of application, age of patient, presence of other scalp infections, patient preference, severity of the infestation, potential for transmission, number of recurrences, and the pattern of resistance in the geographic region.76
Has been recommended as an alternative for treatment of pediculosis pubis† (pubic lice infestation).55 64 69 78 Although CDC states malathion 0.5% may be used for treatment of pediculosis pubis resistant to other pediculicides,69 the malathion preparation commercially available in the US is formulated in a vehicle containing isopropyl alcohol 78%1 and should not be used for treatment of pediculosis pubis since the vehicle may cause burning and irritation of excoriated skin and genitalia.87 88
Topical treatment of pediculosis corporis† (body lice infestation).90 In some cases, body louse infestations may be treated by improved hygiene and by decontaminating clothes and bedding by washing at temperatures that kill lice.61 90 If the infestation is severe, a pediculicide also should be used (e.g., topical permethrin, topical pyrethrins with piperonyl butoxide, topical malathion, oral ivermectin).89 90
Has been used for topical treatment of scabies† (mite infestation), usually as an aqueous lotion.25 30 51 However, the malathion preparation commercially available in the US is formulated in a vehicle containing isopropyl alcohol 78%1 and should not be used for treatment of scabies since the vehicle may cause burning and irritation of excoriated skin and genitalia.87 88
Malathion Dosage and Administration
Measures to Avoid Reinfestation and Transmission
To avoid reinfestation or transmission of pediculosis, most experts recommend that clothing and bed linen that may have been contaminated by the infested individual during the 2 days prior to treatment should be decontaminated (machine-washed in hot water and dried in a hot dryer, dry-cleaned, or treated with an appropriate pesticide) or removed from body contact for ≥72 hours.69 66 79 81
Combs and brushes used by the infected patient may be disinfected by soaking in hot water (temperature >54°C) for 5–10 minutes;4 56 61 66 81 alternatively, they can be soaked in alcohol or a pediculicide for 1 hour.4 6 21 81
In the treatment of pediculosis capitis (head lice infestation), a fine-toothed comb often is recommended to remove any remaining nits (eggs) or nit shells.1 4 6 21 56 66 70 79 81 Some clinicians do not consider nit removal necessary since only live lice can be transmitted, but recommend it for aesthetic reasons and to decrease diagnostic confusion and unnecessary retreatment.54 61 79 Others strongly recommend removal of nits (especially those within 1 cm of the scalp) since no pediculicide is 100% ovicidal and potentially viable nits may remain on the hair after pediculicide treatment.33 70 72 79 Although many schools will not allow children with nits to attend, AAP and other experts consider these no-nit policies excessive.61 77 79
Apply topically to scalp hair as a 0.5% lotion.1
Avoid contact with the eyes.1 Eyes should be closed tightly and covered with a soft towel or washcloth while the lotion is applied to or washed off of scalp hair.1 If contact with the eyes occurs, immediately flush with water.1 If eye irritation persists or if visual changes occur, consult a clinician.1
Apply to dry hair; after application, leave hair uncovered and allow to dry naturally.1
Malathion 0.5% lotion is flammable.1 Do not expose the lotion or hair wetted with the lotion to an open flame, lighted cigarette, or electric heat source (e.g., hair dryer, electric curlers).1 Individuals applying the lotion or patients whose hair is wet with the lotion should refrain from smoking.1
Individuals applying malathion 0.5% lotion should wash their hands thoroughly after application is completed.1
Pediculosis Capitis (Head Lice Infestation)Topical
Children ≥6 years of age: Apply to dry scalp hair in an amount sufficient to thoroughly wet the hair and scalp (including areas on the back of the head and nape of the neck).1 After 8–12 hours, wash hair (including areas on the back of the head and neck) with shampoo and rinse with water.1 Use a fine-tooth (nit) comb to remove dead lice and nits.1
Pediculosis Capitis (Head Lice Infestation)Topical
Apply to dry scalp hair in an amount sufficient to thoroughly wet the hair and scalp (including areas on the back of the head and nape of the neck).1 After 8–12 hours, wash hair (including areas on the back of the head and neck) with shampoo and rinse with water.1 Use a fine-tooth (nit) comb to remove dead lice and nits.1
Cautions for Malathion
History of hypersensitivity to malathion or any ingredient in the formulation.1
Infants and neonates.1 (See Pediatric Use under Cautions.)
Commercially available 0.5% lotion is flammable.1
Do not expose malathion 0.5% lotion or hair wet with the lotion to an open flame, lighted cigarette, or electric heat source (e.g., hair dryers, electric curlers).1 After application, leave the hair uncovered and allow to dry naturally.1
Individuals applying the lotion and those with hair wet with the lotion should refrain from smoking.1
Dermatologic and Sensitivity Reactions
Potential for malathion 0.5% lotion to cause contact allergic sensitization unknown.1 Dermatitis of the scalp has been reported with topical malathion 5% lotion (10 times the usually recommended dosage).16 Contact dermatitis has been reported in individuals exposed to agricultural formulations of malathion.1 73
May be irritating to the skin and scalp;1 slight stinging sensation may occur after application of malathion 0.5% lotion.1 If skin irritation occurs, immediately remove the lotion by washing scalp and hair.1
Eyes should be closed tightly and covered with a soft towel or washcloth while the lotion is applied to or washed off of scalp hair.1
If accidental contact with the eyes occurs, the affected eye(s) should be flushed thoroughly with water.1
Not known whether malathion is distributed into human milk.1 Malathion was not detected in milk samples (minimum limits of detection <5 mcg/L) from nursing women who resided in geographic areas that received extensive aerial spraying with an agricultural formulation of malathion for insect control.48
Use caution when malathion 0.5% lotion is administered to or handled by a nursing woman.1
Keep out of reach of children; use on children only under the direct supervision of an adult.1
Children should be warned to stay away from lighted cigarettes, open flames, and electric heat sources while their hair is wet with the lotion.1 (See Flammability under Cautions.)
Some clinicians recommend that the malathion preparation commercially available in the US not be used on small children or in children with asthma35 51 to prevent exposure to fumes from the isopropyl alcohol vehicle.35 51
Common Adverse Effects
Results of a study in healthy adults using several different aqueous- and alcohol-based formulations of topical malathion 0.5% (not the preparation commercially available in the US) indicate small amounts of the drug are absorbed following application to the scalp and the extent of absorption is similar between aqueous and alcoholic formulations.86
Malathion is absorbed systemically following ingestion,7 20 38 39 40 41 42 43 44 45 46 topical application to skin and mucous membranes,1 5 7 15 20 40 42 47 86 or inhalation of dusts or aerosols.7 20 42
Not known whether malathion crosses the placenta following topical application.1
Not known whether malathion is distributed into milk following topical application.1 Not detected in milk samples (minimum limits of detection <5 mcg/L) from nursing women who resided in geographic areas that received extensive aerial spraying with an agricultural formulation of malathion for insect control.48
In one study following topical application to the scalp of aqueous- or alcohol-based preparations of malathion (not the preparation commercially available in the US), approximately 0.2–3.2% of the applied malathion dose was eliminated in the urine as metabolites within 96 hours.86
Do not expose to an open flame, lighted cigarette, or heat source (e.g., hair dryer, electric curlers).1
Actions and Spectrum
Active in vitro and in vivo against Pediculus humanus var. capitis (head louse) and its nits (eggs)1 3 5 21 24 26 57 62 and Phthirus pubis (pubic or crab louse).24 Also active against Sarcoptes scabiei, the causative agent of scabies.25 30
Therapeutic failure and resistance to malathion has been reported in P. humanus var. capitis34 35 62 75 83 and some strains of P. humanus var. corporis (body louse) in some areas of the world (e.g., United Kingdom, France, Israel).26 36 62 84 87 Clinical importance of these reports as it relates to treatment of lice infections in the US is unclear; prevalence of malathion resistance in the US has not been determined.77 87
Advice to Patients
Importance of using only as directed.1
Advise patients that malathion 0.5% lotion is flammable.1 Importance of staying away from open flames, lighted cigarettes, and electric heat sources (e.g., hair dryers, electric curlers) while the hair is wet with the lotion.1 Importance of not smoking while applying the lotion or while hair is wet with the lotion.1
Importance of thoroughly washing hands after applying malathion 0.5% lotion.1
Advise patients to avoid contact of malathion 0.5% lotion with the eyes.1 If accidental contact with the eyes occurs, immediately flush the affected eye(s) with water.1 If eye irritation persists or if visual changes occur, consult a clinician.1
Importance of immediately consulting clinician and/or poison control center if malathion 0.5% lotion is accidentally ingested.1
Advise patients that a slight stinging sensation may occur when malathion 0.5% lotion is applied.1 If skin irritation occurs, immediately wash lotion from scalp and hair.1 After irritation clears, the lotion can be reapplied.1 If irritation reoccurs, consult a clinician.1
Importance of informing clinician of existing or contemplated concomitant therapy, including prescription and OTC drugs.1
Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.1
Importance of informing patients of other important precautionary information.1 (See Cautions.)
Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.
Ovide (with isopropyl alcohol 78%, terpineol, dipentene, and pine needle oil)
This pricing information is subject to change at the sole discretion of DS Pharmacy. This pricing information was updated 02/2014. Actual costs to patients will vary depending on the use of specific retail or mail-order locations and health insurance copays.
Ovide 0.5% Lotion (TARO): 59/$184.99 or 177/$529.99
AHFS DI Essentials. © Copyright, 2004-2015, Selected Revisions September 1, 2007. American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland 20814.
Only references cited for selected revisions after 1984 are available electronically.
1. Taro Pharmaceuticals. Ovide (malathion) lotion 0.5% prescribing information. Hawthorne, NY; 2005 Jul.
2. Budavari S, O’Neil MJ, Smith A et al, eds. The Merck index. 12th ed. Whitehouse Station, NJ: Merck & Co., Inc; 1996:5740.
3. Anon. Drugs for head lice. Med Lett Drugs Ther. 1997; 39:6-7. [PubMed 9008683]
4. Eichenfield LF, Colon-Fontanez F. Treatment of head lice. Pediatr Infect Dis J. 1998; 17:419-20. [IDIS 407083] [PubMed 9613657]
5. GenDerm Corporation. Ovide lotion (0.5% malathion) monograph. Lincolnshire, IL; 1993.
6. Hogan DJ, Schachner L, Tanglertsampan C. Diagnosis and treatment of childhood scabies and pediculosis. Pediatr Clin North Am. 1991; 38:941-57. [PubMed 1870912]
7. Gosselin RE, Smith RP, Hodge HC et al. Clinical toxicology of commercial products: malathion. 5th ed. Baltimore: Williams & Wilkins Co.; 1984:II-298.K
8. Talcott RE, Denk H, Mallipudi NM. Malathion carboxylesterase activity in human liver and its inactivation by isomalathion. Toxicol Appl Pharmacol. 1979; 49:373-6. [PubMed 494286]
9. Talcott RE, Mallipudi NM, Umetsu N et al. Inactivation of esterases by impurities isolated from technical malathion. Toxicol Appl Pharmacol. 1979; 49:107-12. [PubMed 473195]
10. Mallipudi NM, Talcott RE, Ketterman A et al. Properties and inhibition of rat malathion carboxylesterases. J Toxicol Environ Health. 1980; 6:585-96. [PubMed 7420466]
11. Aldridge WN, Miles JW, Mount DL et al. The toxicological properties of impurities in malathion. Arch Toxicol. 1979; 42:95-106. [PubMed 755464]
12. Talcott RE, Mallipudi NM, Fukuto TR. Malathion carboxylesterase titer and its relationship to malathion toxicity. Toxicol Appl Pharmacol. 1977; 50:501-4.
13. Umetsu N, Mallipudi NM, Toia RF et al. Toxicological properties of phosphorothioate and related esters present as impurities in technical organophosphorus insecticides. J Toxicol Environ Health. 1981; 7:481-97. [PubMed 7288900]
14. Taplin D, Castillero PM, Spiegel J et al. Malathion for treatment of Pediculus humanus var capitis infestation. JAMA. 1982; 247:3103-5. [IDIS 150803] [PubMed 7043013]
15. Walter Z, Czajkowska A, Lipecka K. Effect of malathion on the genetic material of human lymphocytes stimulated by phytohemagglutinin (PHA). Hum Genet. 1980; 53:375-81. [PubMed 6154640]
16. Purdue Frederick Company. The comparative safety and efficacy of Prioderm lotion (0.5% malathion) in the treatment of head louse infestation: a comprehensive review (product promotion). Norwalk, CT; 1983.
17. Ares Mazas ME, Fandino Salorio ML, Silva Villar MJ et al. Efficacy of a malathion lotion for the treatment of pediculosis capitis. Int J Dermatol. 1988; 27:267-8. [PubMed 3391722]
18. Urcuyo FG, Zaias N. Malathion lotion as an insecticide and ovicide in head louse infestation. Int J Dermatol. 1986; 25:60-2. [PubMed 3512461]
19. Klaassen CD. Nonmetallic environmental toxicants: air pollutants, solvents and vapors and pesticides. In: Hardman JG, Limbird LE, Molinoff PB et al, eds. Goodman and Gilman’s the pharmacological basis of therapeutics. 9th ed. New York: McGraw-Hill; 1995:1687-8.
20. Taylor P. Anticholinesterase agents. In: Hardman JG, Limbird LE, Molinoff PB et al, eds. Goodman and Gilman’s the pharmacological basis of therapeutics. 9th ed. New York: McGraw-Hill; 1995:161-76.
21. Meinking TL, Taplin D, Kalter DC et al. Comparative efficacy of treatments for pediculosis capitis infestations. Arch Dermatol. 1986; 122:267-71. [IDIS 212482] [PubMed 2420284]
22. Organophosphate insecticides. In: Reigart JR, Roberts JR, eds. Recognition and management of pesticide poisonings. 5th ed. Washington, DC: US Environmental Protection Agency; 1999:34-47.
23. Quraishi MS. Organophosphorous compounds. In: Biochemical insect control: its impact on economy, environment, and natural selection. New York: John Wiley & Sons; 1977:27-65.
24. Anon. Malathion. (Dutch; translation supplied by Purdue Frederick.) Pharm Weekbl. 1978; 113:328-30.
25. Ailakis JG. Use of a malathion application for the treatment of scabies in an infant. Aust J Hosp Pharm. 1993; 23:30-3.
26. Maunder JW. Use of malathion in the treatment of lousy children. Community Med. 1971; 126:145-7.
27. Coates KG. Control of head infestation in schoolchildren. Community Med. 1971; 126:148-9.
28. Blommers L, van Lennep M. Miscellaneous notes on the toxicity of some insecticides for the head louse, Pediculus capitis de geer (anoplura). Acta Leiden. 1978; 46:9-15. [PubMed 264208]
29. Kimbrough RD, Gaines TB. Effect of organic phosphorus compounds and alkylating agents on the rat fetus. Arch Environ Health. 1968; 16:805-8. [PubMed 5654550]
30. Burgess I, Robinson RJ, Robinson J et al. Aqueous malathion 0.5% as a scabicide: clinical trial. BMJ. 1986; 292:1172. [IDIS 215777] [PubMed 3085770]
31. Machin MGA, McBride WG. Teratological study of malathion in the rabbit. J Toxicol Environ Health. 1989; 26:249-53. [PubMed 2926827]
32. Lindhout D, Hageman G. Amyoplasia congenita-like condition and maternal malathion exposure. Teratology. 1987; 36:7-9. [PubMed 3672379]
33. Reviewers’ comments (personal observations) on Permethrin 84:04:12.
34. Silverton N. Malathion-resistant pediculosis capitis. Br Med J. 1972; 3:646-7. [IDIS 30411] [PubMed 5071715]
35. Anon. Treating head louse infections. Drug Ther Bull. 1998; 36:45-6. [PubMed 9684423]
36. Cole MM, Clark PH, Washington F et al. Resistance to malathion in a strain of body lice from Burundi. J Econ Entomol. 1973; 66:118-9. [PubMed 4690250]
37. Malathion. From: HSDB. Hazardous Substances Data Bank (database). Bethesda, MD: National Library of Medicine, 1999; HSDB No. 0665. From Toxnet website ().
38. Ramu A, Slonim AE, London M et al. Hyperglycemia in acute malathion poisoning. Isr J Med Sci. 1973; 9:631-4. [PubMed 4717946]
39. Goldin AR, Rubenstein AH, Bradlow BA et al. Malathion poisoning with special reference to the effect of cholinesterase inhibition on erythrocyte survival. N Engl J Med. 1964; 271:1289-93. [PubMed 14214635]
40. Wenzl JE, Burke EC. Poisoning from a malathion-aerosol mixture: a case report. JAMA. 1962; 182:495-7. [PubMed 13999973]
41. Richards AG. Malathion poisoning successfully treated with large doses of atropine. Can Med Assoc J. 1964; 91:82-3. [PubMed 14154301]
42. Amos WC, Hall A. Malathion poisoning treated with Protopam. Ann Intern Med. 1965; 62:1013-6. [PubMed 14283379]
43. Crowley WJ, Johns TR. Accidental malathion poisoning. Arch Neurol. 1966; 14:611-6. [PubMed 5935955]
44. Burgess ED, Audette RJ. Case reports: limited effectiveness of charcoal hemoperfusion in malathion poisoning. Pharmacotherapy. 1990; 10:410-2. [IDIS 387537] [PubMed 2287563]
45. Morgade C, Barquet A. Body distribution of malathion and its metabolites in a fatal poisoning by ingestion. J Toxicol Environ Health. 1982; 10:321-5. [PubMed 7143485]
46. Jadhav RK, Sharma VK, Rao GJ et al. Distribution of malathion in body tissues and fluids. Forensic Sci Int. 1992; 52:223-9. [PubMed 1601353]
47. Wester RC, Maibach HI, Bucks DAW et al. Malathion percutaneous absorption after repeated administration to man. Toxicol Appl Pharmacol. 1983; 68:116-9. [IDIS 169802] [PubMed 6845371]
48. Lonnerdal B, Asquith MT. Malathion not detected in breast milk of women living in aerial spraying areas. N Engl J Med. 1982; 307:439. [IDIS 154355] [PubMed 7088119]
49. Murphy SD. Malathion inhibition of esterases as a determinant of malathion toxicity. J Pharmacol Exp Ther. 1967; 156:352-65. [PubMed 6026264]
50. Lyon J, Taylor H, Ackerman B. A case report of intravenous malathion injection with determination of serum half-life. J Toxicol Clin Toxicol. 1987; 25:243-9. [IDIS 233459] [PubMed 3612901]
51. Parfitt K, ed. Martindale: the complete drug reference. 32nd ed. London: The Pharmaceutical Press; 1999:1407-8.
52. Mathias RG, Huggins DR, Leroux SJ et al. Comparative trial of treatment with Prioderm lotion and Kwellada shampoo in children with head lice. Can Med Assoc J. 1984; 130:407-9. [PubMed 6198057]
53. Anon. Drugs for parasitic infections. Med Lett Drugs Ther. Aug 2004. From the Medical Letter web site ()
54. Wilson DC, Leyva WH, King LE. Arthropod bites and stings. In: Fitzpatrick TB, Eisen AZ, Wolff K et al, eds. Dermatology in general medicine. Vol II. 4th ed. New York: McGraw-Hill, Inc.; 1993:2810-26.
55. Mathieu ME, Wilson BB. Lice (pediculosis). In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas, and Bennett’s principles and practices of infectious diseases. 5th ed. New York: Churchill Livingstone; 2000:2972-3.
56. Vander Stichele RH, Dezeure EM, Bogaert MG. Systematic review of clinical efficacy of topical treatments for head lice. BMJ. 1995; 311:604-8. [IDIS 353413] [PubMed 7545045]
57. Chosidow O, Chastang C, Brue C et al. Controlled study of malathion and d-phenothrin lotions for Pediculus humanus var capitis-infested schoolchildren. Lancet. 1994; 344:1724-7. [IDIS 339908] [PubMed 7997000]
59. Tuthill JWG. Toxic hazards: malathion poisoning. N Engl J Med. 1958; 258:1018-9. [PubMed 13541706]
60. Brown S, Becher J, Brady W. Treatment of ectoparasitic infections: review of the English-language literature, 1982-1992. Clin Infect Dis. 1995; 20(Suppl 1):S104-9. [IDIS 345865] [PubMed 7540875]
61. American Academy of Pediatrics. 2006 Red Book: Report of the Committee on Infectious Diseases. 27th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2006.
62. Anon. Malathion for treatment of head lice. Med Lett Drugs Ther. 1999; 41:73-4. [PubMed 10603987]
63. Doss S, Powell CA, Miller AJ. Phenothrin lotion, the latest recruit in the battle against headlice: the results of two controlled comparative studies. J R Soc Health. 1991; 111:47-50. [PubMed 1903813]
64. Rundle PA, Hughes DS. Phthirus pubis infestation of the eyelids. Br J Ophthalmol. 1993; 77:815-6. [PubMed 8110680]
65. Burkhart CG, Burkhart CN, Burkhart KM. An assessment of topical and oral prescription and over-the-counter treatments for head lice. J Am Acad Dermatol. 1998; 38:979-82. [IDIS 405854] [PubMed 9632008]
66. Food and Drug Administration. Pediculicide drug products for over-the-counter human use: establishment of a monograph. 21 CFR Part 358. Proposed rule. [Docket No. 81N-0201] Fed Regist. 1982; 47:28312-21. (IDIS 152095)
67. Lifshitz M, Shahak E, Sofer S. Carbamate and organophosphate poisoning in young children. Pediatr Emerg Care. 1999; 15:102-3. [PubMed 10220078]
68. Namba T, Nolte CT, Jackrel J et al. Poisoning due to organophosphate insecticides: acute and chronic manifestations. Am J Med. 1971; 50:475-92. [PubMed 4324629]
69. Centers for Disease Control and Prevention. Sexually transmitted diseases treatment guidelines 2006. MMWR Recomm Rep. 2006; 55(RR-11):1-94.
70. Burkhart CN, Burkhart CG, Pchalek I et al. The adherent cylindrical nit structure and its chemical denaturation in vitro: an assessment with therapeutic implications for head lice. Arch Pediatr Adolesc Med. 1998; 152:711-2. [PubMed 9667548]
71. Bardin PG, van Eeden SF, Moolman JA et al. Organophosphate and carbamate poisoning. Arch Intern Med. 1994; 154:1433-41. [IDIS 337252] [PubMed 8017998]
72. Burkhart CN, Stankiewicz BA, Pchalek I et al. Molecular composition of the louse sheath. J Parasitol. 1999; 85:559-61. [PubMed 10386454]
73. Milby TH, Epstein WL. Allergic contact sensitivity to malathion. Arch Environ Health. 1964; 9:434-7. [PubMed 14185548]
74. Balaji M, Sasikala K. Cytogenetic effect of malathion in in vitro culture of human peripheral blood. Mutat Res. 1993; 301:13-7. [PubMed 7677938]
75. Meinking TL, Entzel P, Villar ME et al. Comparative efficacy of treatments for pediculosis capitis infections. Arch Dermatol. 2001; 137:287-92. [IDIS 461253] [PubMed 11255326]
76. Jones KN, English JC. Review of common therapeutic options in the United States for the treatment of pediculosis capitis. Clin Infect Dis. 2003; 36:1355-61. [IDIS 511964] [PubMed 12766828]
77. Roberts RJ. Head lice. N Engl J Med. 2002; 346:1645-50. [IDIS 481320] [PubMed 12023998]
78. Wendel K, Rompalo A. Scabies and Pediculosis pubis: an update of treatment regimens and general review. Clin Infect Dis. 2002; 35(Suppl 2):S146-51.
79. American Academy of Pediatrics. Head lice. Pediatrics. 2002; 110:638-43. [IDIS 486240] [PubMed 12205271]
80. Lindane Shampoo, USP, 1% prescribing information. From the FDA web site (). Accessed 2003 Apr 4.
81. Centers for Disease Control and Prevention. Treating head lice. From the CDC website () Accessed 2003 Aug 5.
82. Dawes M. Evidence for double resistance to permethrin and malathion in head lice. Br J Dermatol. 1999; 142:1047-70.
83. Downs AMR, Stafford KA, Harvey I et al. Evidence for double resistance to permethrin and malathion in head lice. Br J Dermatol. 1999; 141:508-11. [IDIS 435234] [PubMed 10583056]
84. Meinking TL, Serrano L, Hard B et al. Comparative in vitro pediculicidal efficacy of treatments in a resistant head lice population in the United States. Arch Dermatol. 2002; 138:220-224. [PubMed 11843643]
85. Yoon KS, Gao JR, Lee SH et al. Permethrin-resistant human head lice, Pediculus capitis, and their treatment. Arch Dermatol. 2003; 139:994-1000. [PubMed 12925385]
86. Dennis GA, Lee PN. A phase I volunteer study to establish the degree of absorption and effect on cholinesterase activity of four head lice preparations containing malathion. Clin Drug Invest. 1999; 18:106-15.
87. Taro Pharmaceuticals, Hawthorne, NY: Personnel communication.
88. Reviewer comments (personal observations).
89. Centers for Disease Control and Prevention. Body lice infestation. From the CDC website () Accessed 2007 Jun 14.
90. Flinders DC, De Schweinitz P. Pediculosis and scabies. Am Fam Physician. 2004; 69:341-50. [IDIS 510826] [PubMed 14765774]