Natroba (Spinosad) - Topical

What Is Natroba?

Natroba (spinosad) is an antiparasitic topical medication used to treat head lice or scabies. Specifically, Natroba is available for people 6 months and older with head lice and people 4 years and older with scabies. This topical drug is classified as a pediculicide.

Pediculicide refers to a category of antiparasitic drugs, often called agents, that work to kill lice or other parasites.

Natroba overstimulates the parasites’ nervous system, leading to paralysis and death. This medication kills lice, scabies, and their eggs (nits).

In general, head lice and scabies are caused by two different types of parasitic insects.

While also available as a generic product called spinosad (the active ingredient in Natroba), Natroba is a brand-name drug that comes in a bottle containing a thick, orange liquid suspension.

The liquid is to be applied topically to the scalp for treating head lice or to the skin for treating scabies.

Drug Facts

Generic Name: Spinosad

Brand Name(s): Natroba

Drug Availability: Prescription

Administration Route: Topical

Therapeutic Classification: Pediculicide

Available Generically: No

Controlled Substance: N/A

Active Ingredient: Spinosad

Dosage Form(s): Powder for iquid suspension

What Is Natroba Used For?

The Food and Drug Administration (FDA) has approved Natroba topical liquid suspension to treat the following:

  • Head lice on the scalp and hair of adults and children 6 months and older. Head lice is an infestation of Pediculus humanus capitis, affecting the scalp and hair on the head. Lice can be seen with the naked eye.
  • Scabies in adults and children 4 years of age and older. Scabies is an itchy skin rash caused by Sarcoptes scabiei, a mite. These tiny parasites require a magnifying glass or microscope to be seen.

How to Use Natroba

Natroba should be applied to the scalp or skin. Avoid getting this medication in the mouth, eyes, or vagina. 

The instructions for applying Natroba depend on whether you are treating head lice or scabies. Be sure to follow your healthcare provider’s instructions.

Here are Natroba’s instructions for treating head lice:

  • Shake the bottle well before use.
  • Apply enough Natroba to cover the dry scalp, then apply to the entire length of dry hair. You may need to use the whole bottle if you have long hair.
  • Leave on for 10 minutes, then rinse off with warm water.
  • Repeat treatment only if live lice are seen seven days after the first treatment. 

Here are Natroba’s instructions for treating scabies:

  • Shake the bottle well before use.
  • Apply enough Natroba to cover your entire body, from the neck to the toes, including the soles of your feet. You may need someone to help apply the medication to your back.
  • If you are bald or balding, you should also apply Natroba to the scalp, hairline, forehead, and temples.
  • Wait 10 minutes before getting dressed to allow the medication to absorb into the skin and dry.
  • Leave on the skin for at least six hours, then shower or bathe.

Ask your healthcare provider if you have any questions about using Natroba.

Storage

Natroba is a liquid suspension that comes in a bottle. Store Natroba at room temperature. Moreover, be sure to keep out of reach of children and pets and avoid storing in an area susceptible to high levels of moisture (e.g., the bathroom).

Discard all unused and expired drugs. Do not toss them down the drain or the toilet.

If you have questions about the best ways of disposing of your medicine, ask your pharmacist. Check out local drug take-back programs in your area.

How Long Does Natroba Take to Work?

Natroba should kill head lice within 10 minutes. A second treatment should be used if any live lice are seen seven days later. Nit combing isn’t required after Natroba treatments, but doing so helps to remove dead lice and eggs. It may take a few days for scalp itchiness to go away. It takes up to six hours for Natroba to kill scabies mites.

If skin itchiness persists, your healthcare provider may recommend ways to ease this symptom, such as taking an antihistamine (drugs used to treat allergies or common cold symptoms).

What Are the Side Effects of Natroba?

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a medical professional. You may report side effects to the FDA at fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

Natroba’s clinical trial results did not report many common side effects.

However, the existing, documented side effects may vary depending on whether you use Natroba to treat head lice or scabies.

Common side effects of Natroba for head lice include:

Common side effects of Natroba for scabies include:

  • Irritation, pain, or burning sensation at application sites
  • Skin dryness

If skin or eye irritation occurs, rinse with water immediately, then contact your healthcare provider.

Severe Side Effects

No severe side effects have been reported with Natroba use. However, it is possible to have an allergic reaction to any medication.

Symptoms of an allergic reaction can include:

Report Side Effects

Natroba may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Natroba Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

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 topical dosage form (suspension):
    • For head lice:
      • Adults and children 6 months of age and older—Apply directly to dry hair and scalp one time only. If you need a second treatment, it should be spaced 1 week apart.
      • Children younger than 6 months of age—Use is not recommended.
    • For scabies:
      • Adults and children 4 years of age and older—Apply directly to skin one time only.
      • Children younger than 4 years of age—Use and dose must be determined by your doctor.

Missed Dose

Natroba is usually a one-time treatment, so missed doses shouldn’t be a concern. 

If you use Natroba to treat head lice, be sure to check for live lice seven days after the first treatment. If you find live lice, use a second treatment.

This is important because if the second treatment is missed, the lice infestation may return or spread to others.

Modifications

Potential users should note the following before beginning Natroba:

Severe allergic reaction: Avoid using Natroba if you have a known allergy to it or its ingredients. Ask your healthcare provider for a complete list of the ingredients if you're unsure.

Pregnancy: Spinosad, the active ingredient in Natroba, is not absorbed following topical application, and parental use is not expected to result in fetal exposure to the drug. Nonetheless, let your healthcare provider know if you're pregnant or plan to become pregnant, and talk to them about the benefits and risks of taking Natroba during pregnancy.

Breastfeeding: Spinosad is not absorbed by the parent following topical application. Therefore, breastfeeding is not expected to result in the child's exposure to spinosad. Nonetheless, talk with your healthcare provider if you plan to breastfeed. You can weigh the benefits and risks of taking spinosad while nursing and discuss how to feed your baby.

Adults over 65: In limited clinical studies, people in this age group did not respond differently from younger adults. However, some older adults might be more sensitive to Natroba's side effects.

Children: The safety and effectiveness of Natroba for the topical treatment of head lice infestation have been established in children 6 months of age and older. However, it's recommended that users are at least 4 years old if diagnosed with scabies.

Overdose: What Happens If I Use Too Much Natroba?

Natroba is only intended for use on the scalp or skin. If you swallow Natroba, seek immediate medical attention.

What Happens If I Overdose on Natroba?

If you think you or someone else may have overdosed on Natroba, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Natroba, call 911 immediately.

Precautions

Drug Content Provided and Reviewed by IBM Micromedex®

This medicine contains benzyl alcohol which may cause serious reactions to newborn, premature, or low-birthweight infants. Check with your doctor if you are concerned.

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

To prevent spread of lice or scabies: Dry-clean or wash your clothes, bedding, and personal items (eg, washcloths, towels, hats, scarves, combs, brushes, hairpieces, and wigs) in hot, soapy water and dry them in a hot dryer.

Do not use this medicine for a skin, hair, or scalp problem that has not been checked by your doctor.

What Are Reasons I Shouldn’t Take Natroba?

Avoid Natroba if the following applies:

Severe allergic reaction: Avoid using Natroba if you have a known allergy to it or its ingredients. Ask your healthcare provider for a complete list of the ingredients if you're unsure.

What Other Medications Interact With Natroba?

There are no specific drug interactions known for topical Natroba. For more detailed interaction information, talk to your healthcare provider.

Be sure to tell your healthcare provider about any other medicines you take, including prescription medications, over-the-counter (OTC) drugs, vitamins, herbs, or dietary supplements.

What Medications Are Similar?

The following lists of medicines are considered alternatives to Natroba. They should not be used together with Natroba. 

Other over-the-counter topical treatments for head lice include the following:

The following prescription topical medications may be used to treat scabies:

  • Elimite (permethrin 5%)
  • Eurax (crotamiton)
  • Lindane
  • Malathion

Consult your healthcare provider if you have questions about medications similar to Natroba.

Frequently Asked Questions

  • What is Natroba used for?

    Natroba (spinosad) is an antiparasitic topical medication used to treat head lice or scabies. Natroba is available in the form of a liquid suspension and is classified as a pediculicide. It is available for people six months and older with head lice and people four years and older with scabies.

  • Is Natroba available over-the-counter?

    No. Natroba is only available by prescription.

  • How does Natroba compare to Nix?

    Nix (permethrin 1%) is an OTC treatment for head lice. It contains the active ingredient permethrin 1%. In many areas, lice have become resistant to permethrin.

    In clinical trials, spinosad was shown to be more effective at getting rid of head lice than permethrin 1%.

How Can I Stay Healthy While Taking Natroba?

It can be stressful dealing with lice or scabies, but neither one causes serious harm.

If someone in the household has head lice or scabies, all household members should typically be treated to prevent reexposure and possible reinfestation.

Be sure to follow your healthcare provider’s instructions for washing bedding, clothing, and other personal care items to prevent re-infestation.

If you’re using Natroba to treat head lice, check everyone in your household for lice the week following treatment.

If you’re using Natroba to treat scabies, ​​treatment is typically recommended for all household members, especially for those who’ve had skin-to-skin contact.

10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Natroba (spinosad) prescribing information.

  2. ScienceDirect. Pediculicide.

  3. Aditya S, Rattan A. Spinosad: an effective and safe pediculicide. Indian Dermatol Online J. 2012;3(3):213-214. doi:10.4103/2229-5178.101825

  4. DailyMed. Label: spinosad suspension.

  5. Food and Drug Administration. Treating and preventing head lice.

  6. Centers for Disease Control and Prevention. Parasites: scabies.

  7. American College of Allergy, Asthma & Immunology. Drug allergies.

  8. Prescribers' Digital Reference. Spinosad - drug summary.

  9. Centers for Disease Control and Prevention. Lice: parasites treatment.

  10. Centers for Disease Control and Prevention. Parasites - scabies. medications.

By Patricia Weiser, PharmD
Patricia Weiser, PharmD, is a licensed pharmacist and freelance medical writer. She has more than 14 years of professional experience.