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Spinosad (Monograph)

Brand name: Natroba
Drug class: Scabicides and Pediculicides
Chemical name: (2R,3aS,5aR,5bS,9S,13S,14R,16aS,16bR)-2-[(6-Deoxy-2,3,4-tri-O-methyl-α-l-mannopyranosyl)oxy]-13-[[(2R,5S,6R)-5-(dimethylamino)tetrahydro-6-methyl-2H-pyran-2-yl]oxy]-9-ethyl-14methyl-2,3,3a,5a,5b,6,9,10,11,12,13,14,16a,16b-tetradecahydro-11H-as-indaceno[3,2-d]oxacyclododecin-7,15-dione
Molecular formula: C83H132N2O20C41H65NO10C42H67NO10
CAS number: 168316-95-8

Introduction

Pediculicide.

Uses for Spinosad

Pediculosis

Topical treatment of pediculosis capitis (head lice infestation) in adults and children ≥4 years of age.

AAP usually recommends topical permethrin 1% or topical pyrethrins with piperonyl butoxide for initial treatment; some clinicians suggest spinosad 0.9% suspension may be an alternative, especially for permethrin-resistant pediculosis capitis.

Spinosad Dosage and Administration

General

Measures to Avoid Reinfestation and Transmission

Administration

Topical Administration

Apply topically to scalp and scalp hair as a 0.9% suspension.

For external use only. Do not administer orally or intravaginally; do not apply topically to eyes.

Shake well immediately prior to use.

Apply to dry scalp, and then dry hair, in amount sufficient to completely saturate scalp and hair. (See Dosage under Dosage and Administration.) Leave suspension on hair and scalp for 10 minutes, then thoroughly rinse off with warm (not hot) water. Minimize exposing other areas of skin by performing rinse at a sink (rather than in shower or bath). Hair may be shampooed after suspension is rinsed off.

Avoid contact with eyes. Eyes should be closed tightly and covered with a soft towel or washcloth while the suspension is applied to or washed off of scalp hair. If contact with the eyes occurs, immediately flush with water.

Supervise pediatric patients during application; an adult should apply and rinse the suspension for the child.

Wash hands thoroughly after applying suspension.

Dosage

Pediatric Patients

Pediculosis
Pediculosis Capitis (Head Lice Infestation)
Topical

Children ≥4 years of age: 1 or 2 applications given 7 days apart. Second application necessary only if live lice are observed 7 days after initial application.

Apply to dry scalp and scalp hair in an amount sufficient to thoroughly saturate hair and scalp. Amount required depends on hair length; very thick, medium-length hair or long hair may require up to a full bottle (120 mL). After 10 minutes, thoroughly rinse suspension off with warm water. (See Administration under Dosage and Administration.)

Adults

Pediculosis
Pediculosis Capitis (Head Lice Infestation)
Topical

1 or 2 applications given 7 days apart. Second application necessary only if live lice are observed 7 days after initial application.

Apply to dry scalp and scalp hair in an amount sufficient to thoroughly saturate hair and scalp. Amount required depends on hair length; very thick, medium-length hair or long hair may require up to a full bottle (120 mL). After 10 minutes, thoroughly rinse suspension off with warm water. (See Administration under Dosage and Administration.)

Prescribing Limits

Pediatric Patients

Pediculosis
Pediculosis Capitis (Head Lice Infestation)
Topical

120 mL.

Adults

Pediculosis
Pediculosis Capitis (Head Lice Infestation)
Topical

120 mL.

Special Populations

No special population dosage recommendations.

Cautions for Spinosad

Contraindications

Warnings/Precautions

Warnings

Benzyl Alcohol Toxicity

Contains benzyl alcohol; administration of IV injections preserved with benzyl alcohol has been associated with serious adverse reactions (e.g., gasping syndrome) and death in neonates and low-birthweight infants [off-label]. Syndrome consists of metabolic acidosis, gasping respirations, progressive hypotension, seizures, CNS depression, intracranial hemorrhage, and death in preterm, low-birthweight infants.

Extent of systemic exposure to benzyl alcohol following topical application of spinosad 0.9% suspension is not known; possible increased systemic absorption in neonates and infants <6 months of age. Lower limit for toxicity is unknown. (See Pediatric Use under Cautions.)

Specific Populations

Pregnancy

Category B.

Lactation

No evidence that spinosad is systemically absorbed following topical application; not expected to be present in breast milk.

Spinosad 0.9% topical suspension contains benzyl alcohol; not known if benzyl alcohol is distributed into milk following topical application of the suspension.

Use with caution in nursing women. If used in a lactating woman, she may choose to pump and discard breast milk for 8 hours (i.e., 5 half-lives of benzyl alcohol) after use to avoid infant ingestion of benzyl alcohol. (See Benzyl Alcohol Toxicity under Cautions.)

Pediatric Use

Safety not established in children <4 years of age.

Because spinosad 0.9% topical suspension contains benzyl alcohol, do not use in infants <6 months of age. (See Benzyl Alcohol Toxicity under Cautions.)

Keep out of reach of children; use on children only under the direct supervision of an adult.

Geriatric Use

Insufficient experience in patients ≥65 years of age to determine whether geriatric patients respond differently than younger adults.

Common Adverse Effects

Application site erythema, ocular erythema, application site irritation.

Drug Interactions

No formal drug interaction studies to date.

Spinosad Pharmacokinetics

Absorption

Bioavailability

Apparently not absorbed systemically following topical application.

In a limited number of children 4–15 years of age no detectable plasma spinosad concentrations (quantifiable limit 3 ng/mL) observed after topical application of the suspension.

Commercially available suspension contains benzyl alcohol; bioavailability of benzyl alcohol following topical application of the suspension not evaluated.

Stability

Storage

Topical

Suspension

25°C (may be exposed to 15–30°C).

Keep out of reach of children. (See Pediatric Use under Cautions.)

Actions and Spectrum

Advice to Patients

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

Spinosad

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Topical

Suspension

0.9%

Natroba

ParaPRO

AHFS DI Essentials™. © Copyright 2024, Selected Revisions February 1, 2012. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.

† Off-label: Use is not currently included in the labeling approved by the US Food and Drug Administration.

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