What if spinosad (Natroba) doesn't work to cure my head lice?

You can repeat the process of using spinosad (Natroba) for a second time after 7 days if you still see live lice. Usually, a third time isn't needed. If spinosad (Natroba) still doesn't work even after using it twice, discuss other [options](https://www.goodrx.com/conditions/lice/lice-treatment) with your healthcare provider.

spinosad

Generic Natroba

Used for Lice

Spinosad (Natroba) is typically applied on the scalp or skin to treat head lice or scabies infestation. Depending on the condition, it can be used on children as young as 6 months old. This medication can be messy to use since you'll need a lot of the product for it to work properly.

Reviewed by:

Daisy Chau, PharmD

Cydnee Ng, PharmD

Last reviewed on November 16, 2022

What is Spinosad (Natroba)?

What is Spinosad (Natroba) used for?

Head lice
Scabies

How Spinosad (Natroba) works

Spinosad (Natroba) is an antiparasitic medication. It works by acting on the nervous system in parasitic insects: lice and mites (which cause scabies). The medication causes their muscles to contract too often, eventually paralyzing and killing these insects.

Drug facts

Common Brands	Natroba
Drug Class	Antiparasitic agent
Controlled Substance Classification	Not a controlled medication
Generic Status	Lower-cost generic available
Availability	Prescription only

Common Brands

Natroba

Drug Class

Antiparasitic agent

Controlled Substance Classification

Not a controlled medication

Generic Status

Lower-cost generic available

Availability

Prescription only

Side effects of Spinosad (Natroba)

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

Redness on scalp (3%)
Irritation at the application site (2-3%)
Eye redness (2%)
Dry skin (2%)

Less Common Side Effects

Hair loss

Source: DailyMed

The following Spinosad (Natroba) side effects have also been reported

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

Itching, burning, flaking, or redness of the scalp

redness of the eye or skin

Rare

Dry skin

dryness of the scalp

hair loss

thinning of the hair

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Get your GoodRx coupon

Avg retail price

$291.87(Save 58.41%)

GoodRx discount

$121.38

See prices

Pros and cons of Spinosad (Natroba)

Pros

Can actually cure the condition after one or two treatments
Kills both live lice and their eggs
Also available as a lower-cost generic

Cons

Can be messy to apply and you might need someone to help
Can cause skin redness or irritation
Not safe for children younger than 6 months old

Pharmacist tips for Spinosad (Natroba)

Before you start using spinosad (Natroba), make sure you read the Instructions for Use. You can also watch helpful administration videos from the manufacturer for treating head lice and scabies with the medication.
Don't forget to wash your hands before and after you apply spinosad (Natroba).

For head lice

Only apply spinosad (Natroba) to dry hair and scalp. Make sure to completely cover both the scalp and hair. Keep your eyes closed until you rinse the medication off to avoid getting it into the eyes.
After you apply, leave spinosad (Natroba) on for 10 minutes. Start timing after your scalp and hair gets fully covered with medication. Then, rinse the area well with warm water.
You can use shampoo in your hair anytime after spinosad (Natroba) is completely rinsed off.
If you see any live lice 7 days after the first time you use spinosad (Natroba), repeat treatment again.
Nit combing after using spinosad (Natroba) isn't required, but you can use a fine-tooth comb to remove treated lice and nits if desired.

For scabies

Apply spinosad (Natroba) to all parts of your body, from your neck to the bottom of your feet. Don't forget to apply it to any folds in the skin, between your fingers and toes, and even under your finger and toe nails. If you have a balding scalp, also apply the medication to the scalp, hairline, temples, and forehead.
After you apply, leave spinosad (Natroba) on for 10 minutes. Start timing after your body gets fully covered with medication. When the 10 minutes are up, you can put your clothes on.
Avoid showering or bathing until at least 6 hours after spinosad (Natroba) has dried on your skin.

Common questions about Spinosad

It depends, but what's more important is that you need to fully cover the area with Spinosad. If you're using the medication for head lice, you might need to use an entire bottle if you have very thick or long hair; you might need less than an entire bottle if you have thinner or shorter hair. If you're using Spinosad to treat scabies, how much you use depends on your body size since it needs to completely cover the body. If you don't apply enough of the medication, some of the insects might survive and lead to continued infestation.

Pretty well. In studies, up to 87% of people who used Spinosad were free of head lice 2 weeks after the last treatment. This is compared to those who used another medication called permethrin (Nix); only up to 45% of people were free of head lice 2 weeks after the last permethrin (Nix) treatment.

You can repeat the process of using Spinosad for a second time after 7 days if you still see live lice. Usually, a third time isn't needed. If Spinosad still doesn't work even after using it twice, discuss other options with your healthcare provider.

You can, but you'll need to take some extra steps for safety. While Spinosad isn't likely to be found in breast milk, it's still important to lessen any potential exposure to the baby. So it's recommended that you wash the breast with soap and water to make sure any trace of Spinosad is gone before breastfeeding.

In addition to using Spinosad, washing items in hot water or dry cleaning is key. To stop lice from spreading, be sure to wash or dry clean all clothing, bedding, and towels. Also wash other items that have touched your hair including combs and brushes. To stop scabies from spreading, also wash any clothing, bedding, and towels that you've used within 3 days before you applied the treatment. If you have items you can't wash or dry clean, you can place them in a sealed plastic bag for at least 3 days.

Risks and warnings for Spinosad (Natroba)

Spinosad (Natroba) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

Harm to infants from benzyl alcohol

Risk Factors: Age younger than 6 months

Spinosad (Natroba) contains benzyl alcohol, which can be dangerous for infants younger than 6 months old. That's why the medication can't be used in anyone younger than 6 months old, regardless of the condition. If exposed to benzyl alcohol, serious side effects can occur, with some even leading to death.

Spinosad (Natroba) dosage

The average cost for 1 bottle of 120ml of 0.9% of Spinosad (Natroba) is $121.38 with a free GoodRx coupon. This is 58.41% off the average retail price of $291.87.

Bottle of suspension

Dosage	Quantity	Price as low as	Price per unit
120ml of 0.9%	1 bottle	$121.38	$121.38

Typical dosage for Spinosad (Natroba)

Head lice: Apply enough of the medication to fully cover your dry scalp and hair. Leave it on for 10 minutes, then rinse it off well with warm water. If there's still lice in your hair 7 days after your first treatment, then you'll have to apply a second treatment.
Scabies: Apply enough of the medication to fully cover your whole body, from your neck to the bottom of your feet. Let it dry for 10 minutes before you put on clothes, and leave it on your skin for at least 6 hours. Then, wash it off by showering or bathing.

Interactions between Spinosad (Natroba) and other drugs

Spinosad (Natroba) may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with Spinosad (Natroba). Please note that only the generic name of each medication is listed below.

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.