Malathion Lotion: Uses, Dosage, Side Effects, Precautions and Alternates

Quick overview

Malathion Lotion (generic name: malathion) is a prescription topical pediculicide used to treat head lice on the scalp and hair. It works by blocking cholinesterase in lice, stopping their nervous system and killing the live lice, and sometimes their eggs. It is applied to dry hair and scalp and is typically used as a single treatment, with a second application possible if lice remain after 7–9 days.

What is Malathion Lotion

Malathion lotion is a prescription medicine that is applied to the skin and hair. It is used to treat head lice, which are tiny insects that live on the scalp.

Malathion Lotion uses

• Treating head lice (Pediculus humanus capitis) and their eggs on the scalp and hair
• Treats head lice
• Kills adult lice
• Helps kill lice eggs
• Treats head lice infestation
• Kills head lice
• Provides topical scalp treatment

Benefits of Malathion Lotion

• Kills active head lice and may also kill some lice eggs
• Can be used when other lice treatments have not worked or are not preferred
• Treats both lice and their eggs
• Applied directly to scalp hair
• May require only one treatment in some cases

How Malathion Lotion works

Malathion works by blocking a protein called cholinesterase in lice. This stops the lice's nervous system from working properly, which kills the live lice and sometimes their eggs too.

Malathion Lotion dosage

Apply the lotion to dry hair and scalp, making sure to cover the back of the head and neck. Let the hair dry naturally in the open air — do not use a hair dryer, straightener, curling iron, or any other heat source. After the hair has dried, shampoo and rinse it out, then use a fine-toothed nit comb to remove dead lice and eggs. Do not smoke or stand near open flames while the hair is wet, since the lotion can catch fire. This treatment is meant to be used one time; do not apply extra amounts. If live lice are still seen about a week later, a second treatment may be needed — check with your healthcare provider. Not for use in infants younger than one year old; one source notes it should not be used in children younger than 6 years old. Wash your hands well after applying the lotion. Wash or dry-clean bedding, clothing, hats, and towels in hot water, and wash combs, brushes, and hair clips in hot water to help stop lice from spreading.

Available forms and strengths

• 0.5% topical lotion

Side effects of Malathion Lotion

Common

• Skin redness or irritation of the skin and scalp
• Stinging sensation on the scalp
• Mild increase in dandruff or dry hair

Serious

• Severe allergic reactions, including breathing problems or wheezing, racing heart, fever, swollen lymph nodes, swelling of the face, lips, mouth, tongue, or throat, trouble swallowing, hives, nausea or vomiting, dizziness or fainting, stomach cramps, and joint pain
• Chemical burns, including second-degree burns, with irritated or stinging skin
• Skin rash, blistering, and peeling of the skin
• Eye irritation, including burning, dryness, itching, discharge, excess tearing, redness, pain, or swelling
• Symptoms of overdose or excessive absorption, such as stomach cramps, anxiety or restlessness, clumsiness, confusion, seizures, diarrhea, difficulty breathing, dizziness, drowsiness, increased sweating, excess saliva or watery eyes, loss of bladder or bowel control, muscle twitching of the eyelids, face, or neck, very small (pinpoint) pupils, slow heartbeat, trembling, or unusual weakness

Warnings and precautions

• This medicine is flammable. Do not use heat sources like hair dryers, straighteners, or curlers on wet hair, and do not smoke or go near open flames until your hair and scalp are completely dry.
• Do not use this medicine in children younger than one year old.
• Only apply this medicine to the scalp and hair. Avoid getting it in your mouth, eyes, eyelashes, eyebrows, ears, nose, lips, or vagina. Close your eyes tightly while applying it.
• Do not use more of this medicine than recommended, since using too much can cause it to run onto other parts of the skin and lead to serious side effects like burns or eye irritation.
• This medicine should not be used in newborns and infants because their scalps are more permeable, which can increase absorption of the drug.
• It is not known if or how this medicine could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant.
• It is not known if this medicine passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed.
• No routine kidney-specific dose adjustment is established for topical use.
• No routine liver-specific adjustment is established.
• It is not known whether drinking alcohol will affect this medicine.
• Malathion lotion does not normally affect driving.

Storage

• Store at room temperature, between 68°F to 77°F (20°C to 25°C)
• Can be exposed to temperatures between 59°F to 86°F (15°C to 30°C) for shorter periods, such as during transport
• Store in a cool, dry place
• Keep the container away from heat sources or open flames
• Flammable — keep away from fire

When to see a doctor

• Stop using the lotion and get help right away if you notice signs of a serious allergic reaction, such as trouble breathing, wheezing, a racing heart, fever, swelling of the face or throat, trouble swallowing, hives, vomiting, dizziness, fainting, stomach cramps, or joint pain.
• If your skin becomes irritated after applying the lotion, stop using it. If irritation happens again after reapplying, wash it off right away and call your healthcare provider.
• If the medicine gets in your eyes, gently flush your eyes with water and tell your healthcare provider if irritation continues or you notice vision changes.
• If you or someone else has used too much of this medicine, get medical help right away or contact a poison control center.
• Get emergency help right away if symptoms of overdose occur, such as stomach cramps, confusion, seizures, trouble breathing, dizziness, drowsiness, excess sweating or watering of the mouth or eyes, loss of bladder or bowel control, muscle twitching, very small pupils, slow heartbeat, trembling, or unusual weakness.

Alternatives

• Permethrin
• Ivermectin lotion
• Spinosad topical suspension
• Pyrethrin-based lice treatments