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Topical malathion is a lotion that is applied to the skin. It is used to treat a condition called head lice, which is caused by tiny insects. The most common side effects are red and irritated skin. If your skin becomes irritated when using this medicine, stop use and wait for the irritation to go away. If your skin becomes irritated again, wash it off and call your healthcare provider.

Uses

What is malathion used for?

Topical malathion is commonly used to treat head lice.

Malathion may also be used for other conditions as determined by your healthcare provider.

How does malathion work (mechanism of action)?

Malathion kills tiny insects, such as head lice, by disrupting their nerves and muscles.

How is malathion supplied (dosage forms)?

Brands and other names

  • Ovide

Dosage forms and strengths

  • 0.5% topical lotion

How should I store malathion?

Topical malathion should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place. Keep the container away from any heat sources or open flames. 

Side Effects

What are the most common side effects of malathion?

The most common side effects of malathion are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

  • Skin redness or irritation

There may be other side effects of malathion that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of malathion?

While less common, the most serious side effects of malathion are described below, along with what to do if they happen.

Severe Allergic Reactions. Topical malathion may cause allergic reactions, which can be serious. Stop using topical malathion and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Burns. In rare cases, topical malathion can cause chemical burns. Symptoms of these burns can include irritated skin, stinging skin, and second-degree burns. If your skin becomes irritated after applying topical malathion, stop applying the medicine. If the irritation goes away, you may continue to apply topical malathion. If your skin becomes irritated again after reapplying the medicine, wash it off right away and call your healthcare provider. 

Warnings & Precautions

Who should not use malathion?

Allergies to Ingredients. People who are allergic to any of the following should not use malathion.

  • Malathion
  • Ovide
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific malathion products they stock.

Infants. Children who are less than one year old should not use topical malathion. 

What should I know about malathion before using it?

Do not use malathion unless it has been prescribed to you by a healthcare provider. Use it as prescribed.

Do not share malathion with other people, even if they have the same condition as you. It may harm them.

Keep malathion out of the reach of children. If your child requires treatment with topical malathion, you or another caregiver should apply the medicine and wash it off for them as directed by your healthcare provider.

Topical malathion should only be applied to the scalp and hair. Do not get the medicine in your mouth, eyes, eyelashes, eyebrows, ears, nose, lips, or vagina. Close your eyes tightly while applying this medicine. If the medicine gets into the eyes, gently flush your eyes with water. 

Apply the lotion to dry hair and wash your hands well when you are finished. Allow your hair and scalp to dry naturally. After eight to 12 hours, shampoo and rinse your hair. Talk to your pharmacist or other healthcare provider if you are uncertain how to apply topical malathion.

Topical malathion is flammable. Do not expose your scalp or hair to any direct heat sources, such as a hair dryer, straightener, or curler, while the medicine is still wet. You should also not smoke or stand near open flames until your scalp and hair have dried completely.

Once you have used topical malathion, it is important to take other steps to stop the spread of head lice. For example, all affected bedding, clothing, hats, and towels should be washed in hot water or dry cleaned. Any affected personal care items, such as brushes, combs, or hair clips, should be washed in hot water. About one week after using this medicine, check for lice again. If you find live lice, speak with your healthcare provider about whether you or your child may need a second treatment.

What should I tell my healthcare provider before using malathion?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if malathion is right for you.

In particular, make sure that you discuss any of the following.

Skin Problems. Tell your healthcare provider if you have any skin conditions or skin allergies.

Pregnancy. It is not known if or how topical malathion could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant.

Breastfeeding. It is not known if topical malathion passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed.

Interactions

Does malathion interact with foods or drinks?

There are no known interactions between topical malathion and foods or drinks.

It is unknown if drinking alcohol will affect topical malathion.

Does malathion interact with other medicines (drug interactions)?

There are no known interactions between topical malathion and other medicines. Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much malathion?

If you or someone else has used too much malathion, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of malathion?

Topical malathion is meant to be applied one time, when needed. Use it as your healthcare provider recommends. Do not apply extra doses.