What is Spinosad: Uses, Dosage, Side Effects and More

Spinosad is a prescription medication that kills head lice and scabies mites on contact. It's derived from naturally occurring bacteria and comes as a topical suspension that you apply directly to your skin or scalp.

This medication offers a gentle yet effective treatment option for parasitic skin conditions. Many people find it easier to use than traditional treatments because it doesn't require combing out dead lice or multiple applications in most cases.

What is Spinosad Used For?

Spinosad treats head lice infestations in adults and children 6 months and older. It's specifically designed to eliminate live lice and their eggs (nits) that have taken up residence on your scalp.

The medication also treats scabies, a skin condition caused by tiny mites that burrow into your skin. These microscopic parasites create intense itching and a characteristic rash that can spread across your body.

Your doctor might recommend spinosad when other lice treatments haven't worked effectively. It's particularly useful for people who have developed resistance to more common treatments like permethrin or pyrethrin-based products.

How Does Spinosad Work?

Spinosad works by attacking the nervous system of lice and mites. It causes these parasites to become overstimulated, leading to paralysis and death within hours of application.

This medication is considered moderately strong but gentler than many chemical alternatives. It targets specific receptors found in insects and mites but not in mammals, which makes it safer for human use.

The active ingredient continues working for several hours after application. This extended action helps ensure that any lice or mites that weren't immediately killed during the initial treatment are eliminated as the medication continues to work.

How Should I Take Spinosad?

Apply spinosad only to dry hair and scalp for lice treatment. Shake the bottle well before each use, then apply enough medication to completely cover your scalp and hair, working it in thoroughly.

You don't need to eat anything special before using spinosad, and it doesn't interact with food. However, avoid getting the medication in your eyes, mouth, or nose during application.

For lice treatment, leave the medication on for 10 minutes exactly, then rinse thoroughly with warm water. For scabies, your doctor will give you specific instructions about how long to leave it on, typically 6-10 hours.

After rinsing, you can shampoo your hair normally. Don't use a conditioner immediately after treatment, as it might reduce the medication's effectiveness.

How Long Should I Take Spinosad For?

Most people need only one treatment with spinosad for head lice. The medication is designed to be effective with a single application, unlike some other treatments that require multiple doses.

Your doctor might recommend a second treatment if live lice are still present 7 days after the first application. This happens occasionally, especially with severe infestations.

For scabies treatment, you'll typically need just one application as well. However, your doctor will monitor your progress and may suggest additional treatments if symptoms persist after 2-4 weeks.

What Are the Side Effects of Spinosad?

Common side effects are generally mild and occur at the application site. Most people experience little to no discomfort when using spinosad properly.

Here are the side effects you might notice, starting with the most common ones:

• Skin redness or irritation where you applied the medication
• Mild burning or stinging sensation during application
• Temporary itching that usually improves within a few hours
• Dry skin or slight flaking in the treated area
• Eye irritation if the medication accidentally gets in your eyes

These reactions typically resolve on their own within a day or two. The itching you experience might actually be from the dying parasites rather than the medication itself.

Serious side effects are rare but require immediate medical attention. Contact your doctor right away if you experience severe skin reactions, widespread rash, difficulty breathing, or signs of an allergic reaction like swelling of your face or throat.

Who Should Not Take Spinosad?

You should not use spinosad if you're allergic to it or any of its ingredients. People with known sensitivities to other topical medications should discuss this with their doctor first.

Infants under 6 months old should not use spinosad for lice treatment. Their skin is more sensitive and may absorb more of the medication than is considered safe.

Pregnant and breastfeeding women should consult their doctor before using spinosad. While studies suggest it's likely safe, your healthcare provider can weigh the benefits against any potential risks for your specific situation.

People with extensive open wounds or severely damaged skin in the treatment area should avoid spinosad. The medication might be absorbed more readily through broken skin, potentially causing stronger side effects.

Spinosad Brand Names

Spinosad is available under the brand name Natroba in the United States. This is the most commonly prescribed formulation for treating head lice and scabies.

Some generic versions may be available, but they contain the same active ingredient and work in the same way. Your pharmacist can help you understand if a generic option is available and appropriate for your needs.

The concentration and formulation remain consistent across different brands, so you can expect similar effectiveness regardless of which version your doctor prescribes.

Spinosad Alternatives

Several other medications can treat head lice and scabies if spinosad isn't right for you. Your doctor might recommend permethrin cream, which is often the first-line treatment for both conditions.

Other alternatives include malathion lotion, benzyl alcohol lotion, and ivermectin cream. Each has different application methods and effectiveness rates, so your doctor will choose based on your specific situation.

Non-medication approaches like wet combing with a fine-toothed comb can help remove lice, though they're typically less effective than prescription treatments. Some people combine these methods with medication for better results.

Is Spinosad Better Than Permethrin?

Spinosad and permethrin are both effective treatments, but they work differently and have distinct advantages. Spinosad often requires only one application, while permethrin typically needs a second treatment after 7-10 days.

Spinosad tends to be more effective against lice that have developed resistance to permethrin-based treatments. If you've tried permethrin without success, spinosad might be a better choice for your situation.

However, permethrin is generally less expensive and has been used safely for many years. Your doctor will consider factors like your treatment history, the severity of your infestation, and your budget when making a recommendation.

Both medications are considered safe and effective when used as directed. The "better" choice depends on your individual circumstances and how your body responds to treatment.