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Quick summary

Type of medicine

Topical Lotion



Active Ingredient


Effective within

Varies (Typically 12-24 hours)

Works by

Paralyzing Lice and Nits

Side effects

Scalp Irritation, Skin Sensitivity

Medication details


Derbac-M is a medicated lotion used for the treatment of head lice (Pediculus humanus capitis) and their eggs (nits). In this comprehensive guide, we will provide you with detailed information about Derbac-M, including its description, directions for use, ingredients, potential side effects, and important warnings.

Derbac-M contains the active ingredient malathion, which is an organophosphorous compound that effectively kills head lice and their eggs. It is widely recognized as a safe and effective treatment for head lice infestations in both adults and children.


Proper application of Derbac-M is crucial for its effectiveness and safety. Follow these directions for use:
Shake the Bottle: Before use, shake the bottle well to ensure that the lotion is thoroughly mixed.
Apply to Dry Hair: Start by applying Derbac-M to dry hair. Ensure that the hair is completely dry before application.
Dispense the Lotion: Dispense a sufficient amount of lotion onto the hair, focusing on the roots and scalp. The amount needed depends on the length and thickness of the hair, so follow the instructions provided with the product.
Thoroughly Massage In: Gently and thoroughly massage the lotion into the hair and scalp. Pay special attention to the areas behind the ears and at the nape of the neck, as lice and nits often cluster in these regions.
Leave for Recommended Time: Leave the lotion on the hair and scalp for the duration specified in the product instructions. This typically ranges from 12 to 24 hours, but it can vary depending on the product.
Rinse and Comb: After the recommended time has passed, wash the hair with a mild shampoo and rinse thoroughly. While the hair is still wet, use a fine-toothed comb to remove any dead lice and nits. This step is crucial for ensuring the removal of lice and their eggs.
Repeat if Necessary: In some cases, a second application of Derbac-M may be required after 7 days to ensure complete elimination of lice and nits. Follow the instructions provided with the product for guidance.
Wash Bedding and Clothing: Wash or dry-clean all bedding, clothing, and personal items that may have come into contact with the infested person's hair. This helps prevent reinfestation.


Derbac-M contains the following active ingredient:
Malathion: Malathion is an organophosphorous compound that works by disrupting the nervous system of head lice, leading to their paralysis and eventual death. It is also effective against lice eggs (nits).

Side Effects

While Derbac-M is generally considered safe and effective when used as directed, some individuals may experience side effects. Common side effects may include:
Scalp Irritation: Mild burning or stinging sensation on the scalp.
Skin Sensitivity: Some individuals may develop skin sensitivity or an allergic reaction to malathion. If you experience severe itching, redness, or swelling, discontinue use and seek medical advice.
Eye Irritation: Avoid contact with the eyes, as Derbac-M can cause eye irritation. Rinse immediately with water if accidental contact occurs.
It's essential to report any unusual or severe side effects to your healthcare provider.


Keep out of reach of children.
Protect from light.
Store below 25°C.
Do not use on infants less than 6 months old.
Consult your doctor before use if you are planning to conceive, pregnant, or breastfeeding.
Avoid prolonged or repeated use.
Use no more than once a week and for no more than 3 consecutive weeks.
Consult your doctor if there is no improvement after 3 weeks of use.
Avoid contact with eyes, mouth, and inside the ears.
For skin use only.
Do not use on broken or infected skin.

External Use Only: Derbac-M is for external use only. Keep it out of reach of children.
Avoid Open Wounds and Eyes: Do not apply Derbac-M to open wounds, cuts, or grazes. Avoid contact with the eyes.
Not for Pregnant or Breastfeeding Individuals: Consult a healthcare provider before using Derbac-M if you are pregnant, planning to become pregnant, or breastfeeding.
Follow Product Instructions: Always follow the product-specific instructions provided with Derbac-M for the recommended application time and any additional steps.
Use with Caution on Sensitive Skin: If you have sensitive or irritated skin, consult a healthcare provider before using Derbac-M.

Medically reviewed and published

  • This page was medically reviewed by Dr Sohaib Imtiaz, Clinical Lead on Oct 5, 2023, 2:45 pm

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Please read our FAQs page to find out more.

How does Derbac-M work to eliminate head lice and nits?

Derbac-M contains the active ingredient malathion, which disrupts the nervous system of head lice, leading to their paralysis and eventual death. It also targets lice eggs (nits), making it an effective treatment for head lice infestations.

Can Derbac-M be used on children and adults alike?

Yes, Derbac-M is suitable for both children and adults. However, it's important to follow the product-specific instructions regarding application and duration based on age and hair type.

What should I do if I accidentally get Derbac-M lotion in my eyes?

If Derbac-M lotion comes into contact with your eyes, rinse them immediately with clean water and consult a healthcare provider if irritation persists. Avoid applying Derbac-M near the eyes to prevent accidental contact.

Can I use Derbac-M if I have a sensitive scalp or skin?

Individuals with sensitive skin or scalp should use Derbac-M with caution. It's advisable to consult a healthcare provider before use if you have a history of skin sensitivity or irritation.

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