malathion (Ovide)

What is malathion, and how does it work (mechanism of action)?

  • Malathion is a pesticide used for killing head lice (Pediculus humanus capitis). It kills head lice and lice eggs by blocking the activity of enzymes (cholinesterase) that breaks-down and inactivates acetylcholine (a neurotransmitter) in head lice. This causes high levels of acetylcholine which leads to death of lice.
  • The FDA approved malathion in August, 1982.

What brand names are available for malathion?


Is malathion available as a generic drug?


Do I need a prescription for malathion?


What are the uses for malathion?

  • Malathion is used for treating people who have head lice and their eggs (Pediculus humanus capitis).

What are the side effects of malathion?

Common side effects of malathion include:

  • Skin irritation
  • Scalp irritation
  • Other side effects include:
  • Mild conjunctivitis from accidental eye contact
  • Possible serious side effects include:
  • Chemical burn (second degree burn)

Malathion is flammable

What is the dosage for malathion?

  1. Dry hair and scalp should be thoroughly wet with malathion lotion, including the back of the head and neck. The hands should be washed after applying.
  2. The hair should not be covered and should dry naturally without using an electric heat source.
  3. The hair should be shampooed after 8 to 12 hours, rinsed and combed with a fine - toothed (nit) comb to remove dead lice and eggs.
  4. Malathion lotion should be applied again if lice are still present after 7 - 9 days.

Which drugs or supplements interact with malathion?


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Is malathion safe to take if I'm pregnant or breastfeeding?

  • Malathion has not been adequately evaluated in pregnant women. Available data from animals suggests that the risk of fetal toxicity is low. It should be used (or handled) during pregnancy only if clearly needed.
  • It is not known whether malathion is excreted in breast milk.

What else should I know about malathion?

What preparations of malathion are available?

  • Lotion: 0.5%

How should I keep malathion stored?

  • Malathion should be stored at room temperature, 20 C - 25 C (68 F - 77 F). It is flammable and should be kept away from heat and open flame.


Malathion (Ovide) is a prescription drug used to treat individuals with head lice and their eggs. Side effects, drug interactions, storage, and pregnancy and breastfeeding safety information should be reviewed prior to taking any medication.

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