MALATHION
Brand names Derbac M, Prioderm, Suleo-M
Used in the following combined preparations None
GENERAL INFORMATION
Malathion is an insecticide used in the treatment of lice and mite infestations. The drug kills parasites by interfering with their nervous system function, causing paralysis and death.
The drug is applied topically, either as a shampoo or a lotion. Malathion is more convenient to use in the form of a lotion, which requires only a single application. However, those with a high alcohol content are unsuitable for small children or asthmatics, who may be affected by the solvent, or for treating crab lice in the genital area.
Because lice develop resistance to insecticides, malathion is used as part of a rotational treatment policy. Once resistance begins to develop to one drug, another product is recommended in order to prevent the emergence of lice resistant to all available treatments. Ask your pharmacist which preparation is currently in use in your area.
QUICK REFERENCE
Drug group Drugs to treat skin parasites
Overdose danger rating Low (medium if swallowed)
Dependence rating Low Prescription needed No
Available as generic No
INFORMATION FOR USERS
Follow instructions on the label. Call your doctor if symptoms worsen.
How taken
Shampoo, lotion.
Frequency and timing of doses
Once only (lotion); once every 3 days for 9 days (shampoo).
Adult dosage range
As directed. Family members and close contacts should also be treated.
Onset of effect
Lotion should be left on for 12 hours (lice), or 24 hours (scabies), before washing off; shampoo should be left on for 5 minutes before being rinsed off.
Duration of action
Until washed off.
Diet advice
None.
Storage
Keep in closed container in a cool, dry place out of the reach of children. Protect from light.
Missed dose
When a repeat application of the shampoo has been missed, it should be carried out as soon as is practicable.
Stopping the drug
Malathion should be applied as a single application or as a short course of treatment.
Exceeding the dose
An extra application is unlikely to cause problems. Take emergency action if the insecticide is accidentally swallowed.
POSSIBLE ADVERSE EFFECTS
Used correctly, malathion preparations are unlikely to produce adverse effects, although
the alcoholic fumes given off by some lotions may cause wheezing in asthmatics.
SPECIAL PRECAUTIONS
Be sure to tell your doctor if:
You have asthma.
Pregnancy
No evidence of risk. It is unlikely that enough malathion would be absorbed after occasional application to affect the developing fetus.
Breast-feeding
No evidence of risk. It is unlikely that enough malathion would be absorbed after occasional application to affect the baby.
Infants and children
No special problems.
Over 60
No special problems.
Driving and hazardous work
No special problems.
Alcohol
No special problems.
INTERACTIONS
None.
PROLONGED USE
Malathion is intended for intermittent use only. The lotions should not be used more than once a week for three weeks at a time.
