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Malathion

Brand names: Ovide

What is malathion used for?

  • Malathion is used to treat head lice.

Before taking malathion, tell your doctor:

  • If you are allergic to malathion; any part of this medicine; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.

This medicine may interact with other drugs or health problems.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take malathion with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take malathion?

  • Tell all of your health care providers that you take malathion. This includes your doctors, nurses, pharmacists, and dentists.
  • This medicine may catch on fire. Do not use near an open flame, while smoking, or near electric heat sources (blow dryer, curling iron). Avoid these heat sources when hair is wet from malathion.
  • This medicine may cause harm if swallowed. If malathion is swallowed, call a doctor or poison control center right away.
  • Use with care in children. Talk with the doctor.
  • Do not give malathion to an infant.
  • Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using malathion while you are pregnant.
  • Tell your doctor if you are breast-feeding. You will need to talk about any risks to your baby.

How is malathion best taken?

Use malathion as ordered by your doctor. Read all information given to you. Follow all instructions closely.

  • Do not take malathion by mouth. Use on your scalp and hair only. Keep out of your mouth, nose, ears, and eyes (may burn).
  • Wash your hands before and after use.
  • Do not wet hair before putting malathion on.
  • Close your eyes tightly when putting malathion on.
  • Apply just enough to wet hair.
  • Work into hair and scalp gently.
  • Let hair air dry and do not cover.
  • Leave on for 8 to 12 hours.
  • Wash hair with a drug-free shampoo.
  • Rinse fully.
  • Use special nit comb or tweezers to get rid of dead nits (lice eggs) from hair.
  • Wash all bedding, towels, and recently worn clothes in hot water or have them dry cleaned.
  • If you get malathion in your eyes, wash right away with water. If you have eye irritation that lasts or a change in eyesight, call your doctor.

What do I do if I miss a dose?

  • Most of the time, only one dose of malathion is needed. If you forget to put on the dose, put it on as soon as you think about it.

What are the side effects of malathion that I need to call my doctor about immediately?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Burning.
  • Stinging.
  • Irritation where malathion is used.

What are some other side effects of malathion?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if you have any side effects that bother you or do not go away.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.

If overdose is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

How do I store and/or throw out malathion?

  • Store at room temperature.
  • Protect from heat or open flame.
  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.

Consumer information use and disclaimer

  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else's drugs.
  • Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about malathion, please talk with your doctor, nurse, pharmacist, or other health care provider.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

This information should not be used to decide whether or not to take malathion or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to malathion. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Source: Wolters Kluwer Health. Last updated April 5, 2023.