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Malathion

Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

Rare

  • Skin rash

Get emergency help immediately if any of the following symptoms of overdose occur:

  • Abdominal or stomach cramps
  • Anxiety or restlessness
  • Clumsiness or unsteadiness
  • Confusion or mental depression
  • Convulsions (seizures)
  • Diarrhea
  • Difficult or labored breathing
  • Dizziness
  • Drowsiness
  • Increased sweating
  • Increased watering of mouth or eyes
  • Loss of bowel or bladder control
  • Muscle twitching of eyelids, face, and neck
  • Pinpoint pupils
  • Slow heartbeat
  • Trembling
  • Unusual weakness

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common or rare

  • Redness, pain, swelling of eye, eyelid, inner lining of eyelid; burning, dry or itching eyes, discharge, excessive tearing
  • Stinging or irritation of scalp

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Precautions

To prevent reinfection or the spreading of the infection to other people, good health habits are also required. These include the following:

  • Wash all clothing, bedding, towels, and washcloths in very hot water or dry-clean them.
  • Wash all hairbrushes and combs in very hot soapy water and do not share them with other people.
  • Clean the house or room by thorough vacuuming.

If you have any questions about this, check with your doctor.

Breathing in even small amounts of carbamate- or organophosphate-type insecticides or pesticides (for example, carbaryl [Sevin], demeton [Systox], diazinon, malathion, parathion, ronnel [Trolene]) may add to the effects of this medicine. Farmers, gardeners, residents of communities undergoing insecticide or pesticide spraying or dusting, workers in plants manufacturing such products, or other persons exposed to such poisons should protect themselves by wearing a mask over the nose and mouth, changing clothes frequently, and washing hands often while using this medicine.

Proper Use

Malathion may cause you to be very sick if it is not used correctly. Do not use it in the mouth because it is harmful if swallowed.

Use this medicine only as directed by your doctor. Do not use more of it, do not use it more often, and do not use it for a longer time than your doctor ordered. To do so may increase the chance of absorption through the skin and the chance of becoming very sick.

To use:

  • Apply malathion by sprinkling on dry hair and rubbing in until the hair and scalp are thoroughly moistened.
  • Immediately after using this medicine, wash your hands to remove any medicine that may be on them.
  • Allow the hair to dry naturally. Use no heat (as from a hair dryer) and leave the hair uncovered.
  • After the medicine has been allowed to remain on the hair and scalp for 8 to 12 hours, wash the hair with a nonmedicated shampoo and then rinse thoroughly.
  • After rinsing, use a fine-toothed comb to remove the dead lice and eggs from the hair.

Keep this medicine away from the eyes. If you should accidentally get some in your eyes, flush them thoroughly with water at once.

This medicine is flammable. Do not use near heat, near open flame, or while smoking.

Head lice can be easily transferred from one person to another by direct contact with clothing, hats, scarves, bedding, towels, washcloths, hairbrushes and combs, or hairs from infected persons. Therefore, all household members of your family should be examined for head lice and receive treatment if they are found to be infected. If you have any questions about this, check with your doctor.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor’s orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For lotion dosage form:
    • For head lice infestations:
      • Adults and children 6 years of age and older—Apply to the hair and scalp one time. Treatment may be repeated after seven to nine days if necessary.
      • Children up to 6 years of age—Use and dose must be determined by your doctor.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Flammable. Keep away from heat and open flame.

Before Using

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

This medicine has been tested in children 6 years of age and older and, in effective doses, has not been shown to cause different side effects or problems than it does in adults. There is no specific information comparing use of malathion in children less than 6 years of age with use in other age groups.

Geriatric

Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of malathion in the elderly with use in other age groups.

Pregnancy

Pregnancy Category Explanation
All Trimesters B Animal studies have revealed no evidence of harm to the fetus, however, there are no adequate studies in pregnant women OR animal studies have shown an adverse effect, but adequate studies in pregnant women have failed to demonstrate a risk to the fetus.

Breastfeeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Anemia (severe) or
  • Brain surgery, recent, or
  • Liver disease or
  • Malnutrition—These conditions may increase the chance of some side effects of malathion
  • Asthma or
  • Epilepsy or other seizure disorders or
  • Heart disease or
  • Myasthenia gravis or other nerve/muscle disease or
  • Parkinson’s disease or
  • Stomach ulcer or other stomach or intestinal problems—Use of malathion may make the condition worse

Description

Malathion belongs to the group of medicines known as pediculicides (medicines that kill lice).

Malathion is applied to the hair and scalp to treat head lice infections. It acts by killing both the lice and their eggs.

This medicine is available only with your doctor’s prescription.