Malathion
FDA Drug Information • Also known as: Malathion, Ovide
- Brand Names
- Malathion, Ovide
- Drug Class
- Cholinesterase Inhibitor [EPC]
- Route
- TOPICAL
- Dosage Form
- LOTION
- Product Type
- HUMAN PRESCRIPTION DRUG
Description
DESCRIPTION Malathion Lotion contains 0.005 g of malathion per mL in a vehicle of isopropyl alcohol (78%), terpineol, dipentene, and pine needle oil. The chemical name of malathion is (±) - [(dimethoxyphosphinothioyl) - thio] butanedioic acid diethyl ester. Malathion has a molecular weight of 330.36, represented by C10H19O6PS2, and has the following chemical structure: malathion_structure.jpg
What Is Malathion Used For?
INDICATIONS AND USAGE Malathion Lotion is indicated for patients infected with Pediculus humanus capitis (head lice and their ova) of the scalp hair.
Dosage and Administration
DOSAGE AND ADMINISTRATION Apply Malathion 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 Malathion 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 Malathion 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.
Side Effects (Adverse Reactions)
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 Malathion Lotion has the potential to cause contact allergic sensitization.
Warnings and Precautions
WARNINGS Malathion 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 Malathion Lotion. Malathion Lotion should only be used on children under the direct supervision of an adult. If Malathion 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 Malathion Lotion, and if irritation reoccurs, consult a physician. Chemical burns including second-degree burns and stinging sensations may occur with the use of Malathion 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 Malathion 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 Malathion Lotion should wash hands after application. Allow hair to dry naturally and to remain uncovered after application of Malathion Lotion. Malathion 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 Malathion Lotion by mouth, seek medical attention immediately. If you are pregnant or nursing, you should contact your physician before using Malathion Lotion. If Malathion 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, Malathion Lotion may be reapplied. If irritation reoccurs, consult a physician. Burns and stinging sensations may occur when using Malathion Lotion. Apply Malathion 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 Malathion Lotion. Anyone applying Malathion 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 Malathion Lotion. Further treatment is generally not necessary. Other family members should be evaluated by a physician to determine if infested, and if so, receive...
Contraindications
CONTRAINDICATIONS Malathion Lotion is contraindicated for neonates and infants because their scalps are more permeable and may have increased absorption of malathion. Malathion Lotion should also not be used on individuals known to be sensitive to malathion or any of the ingredients in the vehicle.
Pregnancy and Breastfeeding
Pregnancy Pregnancy Category B. There was no evidence of teratogenicity in studies in rats and rabbits at doses up to 900 mg/kg/day and 100 mg/kg/day malathion, respectively. A study in rats failed to show any gross fetal abnormalities attributable to feeding malathion up to 2,500 ppm (~ 200 mg/kg/day) in the diet during a three - generation evaluation period. These doses were approximately 40 to 180 times higher than the dose anticipated in a 60 kg adult (based on body surface area and assuming 100% bioavailability). Because animal reproduction studies are not always predictive of human responses, this drug should be used (or handled) during pregnancy only if clearly needed.
Nursing Mothers Malathion in an acetone vehicle has been reported to be absorbed through human skin to the extent of 8% of the applied dose. However, percutaneous absorption from the Malathion Lotion USP, 0.5% formulation has not been studied, and it is not known whether malathion is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Malathion Lotion is administered to (or handled by) a nursing mother.
Overdosage
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.
How Supplied
HOW SUPPLIED Malathion Lotion USP, 0.5%, is supplied in bottles of 2 fl. oz. (59 mL) NDC 68022-0001-1. “Store at 20° to 25°C (68° to 77°F) [See USP controlled Room Temperature]”.
About This Information
This drug information is sourced from FDA-approved labeling via the openFDA database. It is intended for educational and reference purposes only. This is not medical advice. Always consult your healthcare provider before making decisions about medication. Drug information may be updated by the FDA; check with your pharmacist for the most current information.
What are side effects?
Side effects are unwanted reactions that can occur when taking a medication. They range from mild (headache, nausea) to severe (allergic reactions, organ damage). Not everyone experiences side effects, and severity varies. Report any concerning side effects to your doctor.
What are drug interactions?
Drug interactions occur when a medication is affected by another drug, food, or supplement. Interactions can make medications less effective or cause dangerous side effects. Always tell your doctor about all medications and supplements you take.