Malathion

INDICATIONS AND USAGE OVIDE Lotion is indicated for patients infected with Pediculus humanus capitis (head lice and their ova) of the scalp hair.

CLINICAL PHARMACOLOGY Malathion is an organophosphate agent which acts as a pediculicide by inhibiting cholinesterase activity in vivo. Inadvertent transdermal absorption of malathion has occurred from its agricultural use. In such cases, acute toxicity was manifested by excessive cholinergic activity, i.e., increased sweating, salivary and gastric secretion, gastrointestinal and uterine motility, and bradycardia (see OVERDOSAGE ). Because the potential for transdermal absorption of malathion from OVIDE Lotion is not known at this time, strict adherence to the dosing instructions regarding its use in children, method of application, duration of exposure, and frequency of application is required.

DOSAGE AND ADMINISTRATION Apply OVIDE Lotion on DRY hair in amount just sufficient to thoroughly wet the hair and scalp. Pay particular attention to the back of the head and neck while applying OVIDE Lotion. Wash hands after applying to scalp. Allow hair to dry naturally - use no electric heat source, and allow hair to remain uncovered. After 8 to 12 hours, the hair should be shampooed. Rinse and use a fine - toothed (nit) comb to remove dead lice and eggs. If lice are still present after 7 - 9 days, repeat with a second application of OVIDE Lotion. Further treatment is generally not necessary. Other family members should be evaluated by a physician to determine if infested, and if so, receive treatment.

ADVERSE REACTIONS Malathion has been shown to be irritating to the skin and scalp. Other adverse reactions reported are chemical burns including second-degree burns. Accidental contact with the eyes can result in mild conjunctivitis. It is not known if OVIDE Lotion has the potential to cause contact allergic sensitization.

WARNINGS OVIDE Lotion is flammable. The lotion and wet hair should not be exposed to open flames or electric heat sources, including hair dryers and electric curlers. Do not smoke while applying lotion or while hair is wet. Allow hair to dry naturally and to remain uncovered after application of OVIDE Lotion. OVIDE Lotion should only be used on children under the direct supervision of an adult. If OVIDE Lotion comes into contact with the eyes, flush immediately with water. Consult a physician if eye irritation persists. If skin irritation occurs, discontinue use of product until irritation clears. Reapply the OVIDE Lotion, and if irritation reoccurs, consult a physician. Chemical burns including second-degree burns and stinging sensations may occur with the use of OVIDE Lotion. General Keep out of reach of children. Close eyes tightly during product application. If accidentally placed in the eye, flush immediately with water. Use only on scalp hair. Information to Patients OVIDE Lotion is flammable. The lotion and hair wet with lotion should not be exposed to open flames or electric heat sources, including hair dryers and electric curlers. Do not smoke while applying lotion or while hair is wet. The person applying OVIDE Lotion should wash hands after application. Allow hair to dry naturally and to remain uncovered after application of OVIDE Lotion. OVIDE Lotion should only be used on children under the direct supervision of an adult. Children should be warned to stay away from lighted cigarettes, open flames, and electric heat sources while the hair is wet. In case of accidental ingestion of OVIDE Lotion by mouth, seek medical attention immediately. If you are pregnant or nursing, you should contact your physician before using OVIDE Lotion. If OVIDE Lotion comes into contact with the eyes, flush immediately with water. Consult a physician if eye irritation persists or if visual changes occur. If skin irritation occurs, wash scalp and hair immediately. If the irritation clears, OVIDE Lotion may be reapplied. If irritation reoccurs, consult a physician. Burns and stinging sensations may occur when using OVIDE Lotion. Apply OVIDE Lotion on the scalp hair in an amount just sufficient to thoroughly wet hair and scalp. Pay particular attention to the back of the head and neck when applying OVIDE Lotion. Anyone applying OVIDE Lotion should wash hands immediately after the application process is complete. Allow hair to dry naturally and to remain uncovered. Shampoo hair after 8 to 12 hours, again paying attention to the back of the head and neck while shampooing. Rinse hair and use a fine - toothed (nit) comb to remove dead lice and eggs. If lice are still present after 7 - 9 days, repeat with a second application of OVIDE Lotion. Further treatment is generally not necessary. Other family members should be evaluated by a physician to determine if infested, and if so, receive treatment. Laboratory Tests There are no special laboratory tests needed in order to use this medication. Carcinogenesis , Mutagenesis, and Impairment of Fertility Carcinogenesis, mutagenesis and impairment of fertility have not been studied with OVIDE Lotion (0.5% pharmaceutical grade malathion). However, following long-term oral administration of technical grade malathion to rodents via dietary supplementation, increased incidences of hepatocellular neoplastic lesions were observed in B6C3F1 mice dosed for 18 months at malathion doses greater than 1500 mg/kg/day, and in female F344 rats dosed for 2 years at malathion doses greater than 400 mg/kg/day. These tumors occurred only in association with severe hepatic toxicity and chronic suppression of acetylcholinesterase activity, or at doses causing excessive mortality. Based on body surface area, doses at which carcinogenic effects were observed in rodents following life-time exposures to malathion were approximately 14- to 26-fold greater than the maximum dose anticipated in a 10 kg child following a single use

CONTRAINDICATIONS OVIDE Lotion is contraindicated for neonates and infants because their scalps are more permeable and may have increased absorption of malathion. OVIDE Lotion should also not be used on individuals known to be sensitive to malathion or any of the ingredients in the vehicle.

OVERDOSAGE Consideration should be given, as part of the treatment program, to the high concentration of isopropyl alcohol in the vehicle. Malathion, although a weaker cholinesterase inhibitor than some other organophosphates, may be expected to exhibit the same symptoms of cholinesterase depletion after accidental ingestion orally. If accidentally swallowed, vomiting should be induced promptly or the stomach lavaged with 5% sodium bicarbonate solution. Severe respiratory distress is the major and most serious symptom of organophosphate poisoning requiring artificial respiration, and atropine may be needed to counteract the symptoms of cholinesterase depletion. Repeat analyses of serum and RBC cholinesterase may assist in establishing the diagnosis and formulating a long - range prognosis.