CLASSES
Ectoparasiticides, Including Scabicides
DESCRIPTION
Topical pediculicide and scabicide that acts by causing neuronal excitation, paralysis, and death in lice and mites
Used for the treatment of head lice and scabies infestations
Contains benzyl alcohol
COMMON BRAND NAMES
Natroba
HOW SUPPLIED
Natroba/Spinosad Topical Susp: 0.9%
DOSAGE & INDICATIONS
For the treatment of pediculosis capitis (head lice infestation) due to Pediculus capitis.
NOTE: Adjunctive measures for treatment of head lice infection include: use of a fine-tooth comb or special nit comb to remove dead lice and nits; washing personal care items (e.g., combs, brushes, hair clips) in hot water; washing (hot water and hot cycle of dryer for at least 20 minutes) or dry-cleaning all recently worn clothing, hats, bedding, and towels.
Topical dosage
Adults
Apply a sufficient amount of suspension topically to cover dry scalp and hair; up to 1 bottle (120 mL) may be required depending on the length of hair. Leave on for 10 minutes and then rinse thoroughly with warm water. If live lice are still seen 7 days after the first treatment, apply a second treatment.
Infants, Children, and Adolescents 6 months and older
Under the direct supervision of an adult, apply a sufficient amount of suspension topically to cover dry scalp and hair; up to 1 bottle (120 mL) may be required depending on the length of hair. Leave on for 10 minutes and then rinse thoroughly with warm water. If live lice are still seen 7 days after the first treatment, apply a second treatment.
For the treatment of scabies infestation due to Sarcoptes scabiei.
NOTE: As an adjunctive measure for treatment of scabies, machine wash (hot water and hot cycle of dryer for at least 20 minutes) or dry-cleaning all bedding, clothing, and towels that have been used anytime during the 3 days before treatment. Alternatively, the bedding, clothing, and towels may be sealed in a plastic bag for at least 72 hours.
Topical dosage
Adults
Apply a sufficient amount of suspension topically to completely cover the body from the neck to the toes (including the soles of the feet). For patients with balding scalp, also apply to the scalp, hairline, temples, and forehead. Allow the suspension to absorb into the skin and dry for 10 minutes before getting dressed. Leave on the skin for at least 6 hours before showing or bathing.
Children and Adolescents 4 years and older
Under the direct supervision of an adult, apply a sufficient amount of suspension topically to completely cover the body from the neck to the toes (including the soles of the feet). For patients with balding scalp, also apply to the scalp, hairline, temples, and forehead. Allow the suspension to absorb into the skin and dry for 10 minutes before getting dressed. Leave on the skin for at least 6 hours before showing or bathing.
MAXIMUM DOSAGE
Adults
120 mL per application.
Geriatric
120 mL per application.
Adolescents
120 mL per application.
Children
4 years and older: 120 mL per application.
1 to 3 years: 120 mL per application for head lice infestation; safety and efficacy have not been established for scabies infestation.
Infants
6 months or older: 120 mL per application for head lice infestation; safety and efficacy have not been established for scabies infestation.
Less than 6 months: Not recommended.
Neonates
Not recommended.
DOSING CONSIDERATIONS
Hepatic Impairment
Specific guidelines for dosage adjustments in hepatic impairment are not available; it appears that no dosage adjustments are needed.
Renal Impairment
Specific guidelines for dosage adjustments in renal impairment are not available; it appears that no dosage adjustments are needed.
ADMINISTRATION
Topical Administration
Spinosad is administered topically. Avoid contact with eyes, mouth, or any mucus membrane. Do not ingest.
For use on pediatric patients, apply only under direct supervision of an adult.
Other Topical Formulations
Spinosad Topical Suspension
Shake bottle well immediately prior to use.
For treatment of head lice infestations:
Scalp and hair should be dry prior to application.
Apply a sufficient amount of suspension to adequately cover scalp and hair.
Leave on for 10 minutes then thoroughly rinse off with warm water.
Wash hands after use.
For treatment of scabies infestations:
Apply a sufficient amount of suspension to completely cover the body from the neck to the toes (including the soles of the feet). For patients with balding scalp, also apply to the scalp, hairline, temples, and forehead. Ensure suspension is applied to skin folds, between fingers and toes, and under finger and toe nails.
Allow the suspension to absorb into the skin and dry for 10 minutes before getting dressed.
Leave on for at least 6 hours before showering or bathing.
STORAGE
Generic:
- Store at 77 degrees F; excursions permitted to 59-86 degrees F
Natroba:
- Store at 77 degrees F; excursions permitted to 59-86 degrees F
CONTRAINDICATIONS / PRECAUTIONS
Infants, neonates
Spinosad topical suspension contains benzyl alcohol and is not recommended for use in neonates and infants younger than 6 months of age. Intravenous administration of benzyl alcohol at dose greater than 99 mg/kg/day to neonates and low birth-weight infants has resulted in 'gasping syndrome,' which is a potentially fatal condition characterized by metabolic acidosis and CNS, respiratory, circulatory, and renal dysfunction; it is also characterized by high concentrations of benzyl alcohol and its metabolites in the blood and urine. The minimal amount of benzyl alcohol at which toxicity may occur is not known. Premature infants, infants with a low birth weight, and patients who receive a high dose may be more likely to develop toxicity.
Pregnancy
Studies evaluating the use of spinosad during human pregnancy have not been conducted; however, in animal studies involving rats and rabbits, oral administration of the drug during organogenesis produced no evidence of teratogenicity. When administered topically at FDA-approved doses, spinosad is not absorbed systemically. Further, the inactive benzyl alcohol component is not expected to be absorbed through the skin in clinically relevant amounts; therefore, maternal use is not expected to result in fetal exposure.
Breast-feeding
To avoid direct infant exposure, advise lactating mothers receiving treatment with spinosad to wash away the drug from the breast with soap and water before breast-feeding. Spinosad is not systemically absorbed and will not cross into the breast milk. Further, the inactive benzyl alcohol component is unlikely to be absorbed through the skin in clinically relevant amounts; therefore, the infant is not expected to be exposed through breast milk. Permethrin or pyrethrins with piperonyl butoxide are considered compatible with breast-feeding by guidelines for other conditions and may be considered for use as alternatives to spinosad. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally administered drug, health care providers are encouraged to report the adverse effect to the FDA.
ADVERSE REACTIONS
Moderate
erythema / Early / 3.0-3.0
Mild
skin irritation / Early / 1.0-3.0
xerosis / Delayed / 0-2.0
alopecia / Delayed / 0-1.0
DRUG INTERACTIONS
There are no drug interactions associated with Spinosad products.
PREGNANCY AND LACTATION
Pregnancy
Studies evaluating the use of spinosad during human pregnancy have not been conducted; however, in animal studies involving rats and rabbits, oral administration of the drug during organogenesis produced no evidence of teratogenicity. When administered topically at FDA-approved doses, spinosad is not absorbed systemically. Further, the inactive benzyl alcohol component is not expected to be absorbed through the skin in clinically relevant amounts; therefore, maternal use is not expected to result in fetal exposure.
To avoid direct infant exposure, advise lactating mothers receiving treatment with spinosad to wash away the drug from the breast with soap and water before breast-feeding. Spinosad is not systemically absorbed and will not cross into the breast milk. Further, the inactive benzyl alcohol component is unlikely to be absorbed through the skin in clinically relevant amounts; therefore, the infant is not expected to be exposed through breast milk. Permethrin or pyrethrins with piperonyl butoxide are considered compatible with breast-feeding by guidelines for other conditions and may be considered for use as alternatives to spinosad. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally administered drug, health care providers are encouraged to report the adverse effect to the FDA.
MECHANISM OF ACTION
Spinosad is a topically applied pediculicide and scabicide that acts by causing neuronal excitation, paralysis, and death in lice and mites.
PHARMACOKINETICS
Spinosad is applied topically.
Topical Route
After topical administration of the FDA-approved dose of spinosad, clinically significant systemic exposure is not expected. In a pharmacokinetic study of 14 patients aged 4 to 15 years with head lice, spinosad 1.8% was applied to the scalp of each patient and washed off after 10 minutes. Plasma samples were analyzed, and spinosad was found to be below the limit of quantitation (3 ng/mL) in all samples. Plasma concentrations of benzyl alcohol were not determined in these patients. In another head lice infestation study, concentrations of spinosad and benzyl alcohol were assessed in 26 patients aged 6 months to 4 years after topical application of spinosad 0.9% for 10 minutes. Plasma spinosad concentrations were below the limit of quantitation (3 ng/mL) in all samples. Benzyl alcohol concentrations were quantifiable (greater than 1 mcg/mL) in 4 patients in the 6 months to less than 2 years age group and 2 patients in the age group 2 to 4 years; the highest observed concentration was 2.37 mcg/mL. At 12 hours post-treatment, benzyl alcohol concentrations were below the limit of quantitation in all patients. In patients with scabies infestation, a pharmacokinetic study was conducted in 19 pediatric patients aged 5 to 16 years. All patients applied a single spinosad 0.9% treatment from the neck to the soles of the feet. The suspension was allowed to remain on the body for a minimum of 6 hours. Post-treatment plasma sampling found spinosad concentrations were below the limit of quantification (3 ng/mL) in all samples. Benzyl alcohol was quantifiable (greater than 1 mcg/mL) in 6 patients; 3 in the 5 to 9 year age group and 3 in the 10 to 16 year age group. The highest observed concentration was 3.94 mcg/mL at 30 minutes post-treatment in 1 patient. The mean maximum plasma concentration (Cmax), time to peak (Tmax), and exposure (AUC) for benzyl alcohol were 2.737 mcg/mL, 1.42 hours, and 19.24 mcg/mL x hour, respectively. At 6 and 12 hours post-treatment, benzyl alcohol concentrations were below the limits of detection in all patients.