Spinosad, Natroba

Written by Ashley Wong, PharmD
Medically reviewed by Brittany Duke, PharmD, RPh
Updated on October 6, 2023

Spinosad (SPIN oh sad) is a generic medication prescribed for head lice and scabies. Spinosad belongs to two groups of drugs called pediculicides and scabicides.

The Food and Drug Administration (FDA) approves prescription drugs such as spinosad for certain conditions. Approved uses for spinosad are described below.

Use for lice

Doctors may prescribe spinosad for treating head lice. It’s used for this purpose in adults and children ages 6 months and older. It’s usually prescribed as a short-term treatment.

Lice are small insects that feed on blood from your scalp. They are typically found on your head, specifically on your scalp, behind your ears, near your neckline, in your eyebrows, or in your eyelashes. Head lice causes symptoms such as extreme itchiness, a crawling sensation, and sores or scabs due to scratching.

Spinosad is prescribed together with other lice management measures. These include washing clothing items, hats, bedding, and towels in hot water. It also involves washing combs, brushes, and hair clips in hot water, as well as using a special nit comb to remove dead lice and nits from your hair.

Use for scabies

Doctors may prescribe spinosad for treating scabies. It’s used for this purpose in adults and children ages 4 years and older. It’s usually prescribed as a short-term treatment.

Scabies is caused by mites, and it’s a very contagious skin condition. (This means it’s easily passed between people.) It causes a rash and intense itching that’s usually worse at night. The rash may involve tiny bites, hives, or bumps under your skin. Examples of areas affected include the wrist, elbow, and armpit.

Spinosad is prescribed together with other scabies management measures. These include washing bedding, clothing items, and towels in hot water.

Below you’ll find answers to a few commonly asked questions about spinosad.

What brand names are available for spinosad?

Spinosad is a generic medication. Its brand-name version is called Natroba.

A generic medication is an identical copy of the active drug in a brand-name medication. (An active drug is the ingredient that makes a medication work.) Generic drugs are believed to be as effective and safe as brand-name drugs. And generic drugs typically cost less compared to brand-name drugs.

If you have more questions about this, talk with your doctor or pharmacist.

How does spinosad work? And how long does it take to start working?

Spinosad works to treat head lice and scabies by paralyzing and killing the lice or mites involved. The drug starts working right away after it’s applied, and it can treat head lice or scabies within 10 minutes.

If you’d like to know more about this, talk with your doctor or pharmacist.

Spinosad may cause mild or serious side effects. More common mild side effects of spinosad and its serious side effects are listed below. This article doesn’t include all possible side effects of the drug. Side effects can vary based on your age, overall health, and any other medications you take.

To learn more about spinosad’s side effects, ask your doctor or pharmacist. You can also refer to the prescribing information for spinosad listed in the “Resources” section.

Mild side effects

More common mild side effects reported with spinosad are listed below.

This article doesn’t include all possible mild side effects of the drug. To learn more about spinosad’s side effects, refer to the prescribing information for spinosad listed in the “Resources” section.

With many drugs, mild side effects may go away within a few days or a couple of weeks. If the side effects are bothersome, tell your doctor or pharmacist. They may be able to suggest ways to manage them.

Spinosad topical suspension’s mild side effects include:

• redness or discoloration where the medication is applied
• eye redness
• irritation, including pain and burning, where the medication is applied
• dry skin
• mild allergic reaction*

* For details about this side effect, see the “Interactions and warnings for spinosad” section.

Serious side effects

Serious side effects of spinosad are listed below.

This article doesn’t include all possible serious side effects of the drug. To learn more about spinosad’s side effects, refer to the prescribing information for spinosad listed in the “Resources” section.

With many drugs, serious side effects are possible but not common. If you have serious side effects from this drug, call your doctor right away. If you’re having severe symptoms or a medical emergency, call 911 or a local emergency number.

In general, spinosad’s serious side effects include: 

• hair loss
• severe allergic reaction*

* For details about this side effect, see the “Interactions and warnings for spinosad” section.

Below, you’ll find information about spinosad’s possible interactions and warnings.

Interactions of spinosad

Spinosad isn’t known to interact with any medications or supplements. (Interactions can affect how a drug works.) But this doesn’t mean drug interactions with spinosad won’t happen or be reported sometime. For instance, medications created at a later time could interact with spinosad.

Because of this, you should ask your doctor and pharmacist about possible interactions with spinosad. They can check for any interactions that may affect you, such as those with:

• vaccines
• foods or alcohol
• other drugs

Warnings for spinosad

Spinosad should not be used by certain people.

Spinosad could cause harm to people with certain health conditions. This effect is called a drug-condition interaction. Other factors can also affect whether spinosad is a safe option for you. These warnings may differ based on the form of spinosad you use.

Ask your doctor about specific warnings for spinosad, and be sure to tell your doctor about your:

• current health, including any allergies to medications
• past health conditions or surgeries

Allergic reaction

Spinosad can cause an allergic reaction in some people. Severe allergic reactions are rare but possible.

If you’ve had an allergic reaction to spinosad or any of its ingredients, your doctor will likely not prescribe spinosad. They can tell you about medications that are safer options for you.

A mild allergic reaction may cause the following symptoms:

• skin rash
• itchiness
• flushing (temporary warmth, redness, or deepening of skin color)

A severe allergic reaction may cause the following symptoms:

• swelling under your skin, usually in your hands, feet, eyelids, or lips
• swelling of your mouth, throat, or tongue, which can cause breathing problems

If you have an allergic reaction to spinosad, call your doctor right away. If you have severe symptoms, call 911 or a local emergency number.

Overdose of spinosad

You should not use more spinosad than your doctor prescribes. For some drugs, doing so may lead to harmful effects or overdose.

If you think you’ve used too much spinosad, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have concerning symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.

Pregnancy or breastfeeding and spinosad

Information about spinosad and pregnancy and breastfeeding is described below.

Spinosad and pregnancy

It’s not known whether spinosad should be used during pregnancy. If you’re planning a pregnancy or can become pregnant, talk with your doctor before using this medication.

Spinosad and breastfeeding

It’s not known whether spinosad should be used while breastfeeding. If you’re currently breastfeeding or planning to do so, talk with your doctor before using this medication.

Let your doctor know if you have questions about spinosad or would like more details about it.

Here’s a list of some possible questions you may want to ask your doctor:

• How should I apply spinosad?
• How can I lower my risk of side effects with spinosad?
• What are my options if I can’t afford spinosad?
• Are there any alternative medications I can use for my condition?

• Food and Drug Administration. (2023). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm
• Spinosad topical suspension. (2021). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/8e87bd3b-db25-4e97-bf57-96c875f67ce1/spl-doc

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.