Spinosad (Topical)

If you're itching for a quick solution for head lice, Spinosad topical suspension cream may be right for you.


According to the American Centers for Disease Control, head lice is a common condition in school-agers. Roughly 6-12 million cases are reported every year. To tame outbreaks and provide patients with fast relief, doctors sometimes prescribe Spinosad topical suspension cream.

This medicine is available by prescription only under the U.S. trade name Natroba, an FDA approved drug intended for head lice. It is considered safe for use in patients who are four years or older, including seniors over the age of 65.

What Are Head Lice?

Head lice are parasites or tiny insects that have a penchant for making a home in human hair. These are minuscule organisms and to give you some perspective, lice measure roughly the size of a sesame seed. The nits (eggs) are even tinier - around the size of a mustard seed.

While the eggs or nits are white, the live insects themselves range in shades of light brown to black.

Most people assume that pets are the main culprit for spreading head lice. However, the sole hosts of these pesky critters are humans.

The most alarming reason to get rid of head lice, besides the itch, is the fact that head lice are real bloodsuckers. These organisms feed on blood sourced from the scalp in order to survive. If left as-is, head lice could multiply rapidly, causing even greater itchiness and discomfort.

Nevertheless, studies show that head lice do not cause disease. However, head lice could cause secondary infections could occur due to excessive itchiness and abrasion of the skin.

Condition(s) Treated?

  • Head Lice
  • Pediculus Humanus Capitis

Type of Medicine?

  • Pediculicide

Side Effects

When taking Spinosad, users may experience:

  • Burning of the Scalp
  • Excess Flakiness
  • Inflamed or Red Eyes
  • Skin Irritation

Some Rare Side Effects of Spinosad Tropical

Users could also get:

  • Dry Skin or Scalp
  • Thinning or Loss or Hair

These, however, are some of the rare side effects of Spinosad. If these conditions persist, and in particular hair loss, contact your doctor immediately.


The prescribed dosage of Spinosad on average is one full bottle:

  • Children: One Application All Over the Hair and Scalp | One-Use Only
  • Adults: One Application All Over the Hair and Scalp | One-Use Only

Spinosad is supplied in 120 ML bottles, containing 9 mg of spinosad per gram.

Note: Spinosad Topical Application is not intended for use in infants 6 months old and under.

Most over the counter medicines for head lice require multiple applications. However, this prescription is intended for one-time use only - except in extenuating circumstances. If the head lice do not clear up and live lice are detected at a follow-up visit, another dose may be prescribed for 7 days after the initial date of treatment.

How to Use

Follow the directives provided by your pharmacist and/or medical provider. Some of the rules of thumb include practicing the following tips:

  1. 1. Hand Washing: To begin the process and prevent secondary infections, wash your hands thoroughly with a disinfecting soap for roughly two (2) minutes. Rinse under hot running water and dry with a clean towel or disposable cloth or paper product.
  2. 2. Gather Tools: For best results and fewer hassles, gather supplies, such as a:
  • Hair Towel
  • Gloves
  • Fine-Tooth Comb
  • Paper Towel
  • Trash Bag
  1. Use this Step-by-Step Guide for Spinosad:
  • Shake Well: Before applying the recommended dose to the hair and scalp, shake the solution thoroughly for up to one minute to allow for even distribution of the prescription.
  • Leave Hair Dry: Some patients make the mistake of shampooing and conditioning the hair first to remove the head lice. Washing the hair before applying Spinosad is nevertheless counterproductive.
  • Apply to Hair and Scalp: Follow the dosage orders dispensed by your pharmacist and spread the solution throughout the hair and scalp with gloved hands. Separate in sections if needed for more even distribution.
  • Leave In Temporarily - Leave Spinosad in for roughly 10 minutes. Please note that leaving the solution in for a longer period of time could increase the risk of negative side effects, such as hair loss. As a result, be sure to set a timer to rinse within 10 minutes - or as prescribed by your pharmacist.
  • Rinse Thoroughly: The best way to rinse without cross-contamination is under a sink with a faucet rinser. Use warm water to wash the solution out of the hair and scalp completely.
  • Comb the Hair: The next step of the treatment process is mildly labor intensive, but necessary all the same. To remove dead lice, nits, and shells, comb the hair and scalp with a fine-tooth comb. Patients typically report that these nits resemble tiny white specks or spots.

Other Best Practices

For best results, set enough time aside to complete the treatment.

Doctors recommend that an adult or caregiver apply the treatment to children's hair and scalp:


No substantial drug contraindications have been reported for Spinosad topical suspension cream.

Over-the-Counter cosmetics, however, could negatively interact with prescription Spinosad. As a result, ask a medical professional for advice on when you can resume your regular hair care routine.


Before using Spinosad Topical suspension, read the instructions inserted in the pack carefully.

The following section provides a few precautions to help minimize the potential risks of using Spinosad for head lice.

Head Lice Are Contagious

Head lice have been a pervasive parasite that has plagued us for centuries. In fact, remains of dead lice have been found on Egyptian mummies unearthed from a bygone era.

One of the main reasons for its prevalence is that head lice are super easy to transmit through direct contact with an infected party.

Members of the same household, for example, may spread head lice back and forth. The cycle could continue indefinitely if proper measures aren't taken. The following items are some of the most reported means of transporting head lice from one party to another:

  • Clothes
  • Accessories
  • Sheets
  • Towels
  • Wash Clothes
  • Hair Tools (Comb and Brush)

Due to the high-risk of transmission in households, all members should be screened - and ideally by a healthcare professional.

To reduce the chances of transmission, all soft fabrics and hair tools in the house must be washed thoroughly in piping hot soapy water. Heat is a proven way to kill head lice and a host of other germs.

Note: Set your washer and dryer on the highest heat setting possible.

Spinosad: One Part of a Bigger Treatment Plan

Spinosad treatments in and of itself will not completely wipe out head lice infestations in households. Patients will need to follow the complete treatment plan recommended by a healthcare provider to successfully eliminate head lice, which typically includes washing and rinsing soft fibers and hair tools.

Pediatric Use

Based on medical research, Spinosad is not intended for patients who are under the age of 6 months old. The following groups are more susceptible to more severe risks:

  • Newborns
  • Premature Babies
  • Underweight Infants

Spinosad is manufactured with benzyl alcohol, which predisposes infants to severe risks, some potentially fatal.

Pregnant and Nursing Mothers

Even though Spinosad is exclusively applied externally on the skin and the drug cannot be absorbed systematically, it is important to inform your doctor if you are pregnant, nursing, or plan to be - before commencing treatment.

Preexisting Skin Conditions

If you have sensitive skin or a history of allergies to certain medications or products, inform your doctor before using Spinosad.

For Topical Use Only

This medicine is intended for topical use only. In the event of accidental ingestion, call 911 and the American Poison Control Centers immediately at (800) 222-1222.


To maintain the integrity of Spinosad, store at a room temperature of 25ºC (77ºF), and out of the reach of children and pets.

Discard of any unused or expired portion by taking it to a local pharmacy.


Spinosad topical suspension cream is effective for eliminating head lice infestations - a pervasive issue that has plagued us for centuries. Even though head lice aren't dangerous, these critters cause the scalp to itch and also carry a stigma, despite the high rates of infestation year after year.

Patients are able to achieve lice-free status in just one application. If symptoms persist and head lice are not fully exterminated, a second treatment may be prescribed after a 7-day window has lapsed.

The medication is available by prescription only and should be used exactly as ordered. Spinosad is one part of the full treatment plan to exterminate head lice.

As lice infestations are challenging to eliminate, patients must take extra measures to wash all contaminated soft fibers within the household in hot and soapy water. This includes bedding, towels, rags, and all hair tools.

Spinosad topical creams are not recommended for infants under 6 months old as the ingredient, benzyl alcohol, could cause serious and fatal side effects to occur.

Last Reviewed:
December 22, 2017
Last Updated:
April 05, 2018