Ivermectin

Pronunciation

Class: Scabicides and Pediculicides
VA Class: AP300
Chemical Name: A mixture of Ivermectin Component B1a (2aE,4E,8E) - (5′S,6S,6′R,7S,11R,13R,15S,17aR,20R,20aR,20bS) - 6′ - (S) - sec - butyl - 3′,4′,5′,6,6′,7,10,11,14,15,17a,20,20a,20b - tetradecahydro - 20,20b - dihydroxy - 5′,6,8,19 - tetramethyl - 17 - oxospiro[11,15 - methano - 2H,13H,17H - furo[4,3,2 - pq][2,6] - benzodioxacyclooctadecin - 13,2′ - [2H]pyran] - 7 - yl - 2,6 - dideoxy - 4 - O - (2,6 - dideoxy - 3 - O - methyl - α - l - arabino - hexopyranosyl) - 3 - O - methyl - α - l - arabino - hexopyranoside) and Ivermectin Component B1b (2aE,4E,8E) - (5′S,6S,6′R,7S,11R,13R,15S,17aR,20R,20aR,20bS) - 3′,4′,5′,6,6′,7,10,11,14,15,17a,20,20a,20b - tetradecahydro - 20,20b - dihydroxy - 6′ - isopropyl - 5′,6,8,19 - tetramethyl - 17 - oxospiro[11,15 - methano - 2H,13H,17H - furo[4,3,2 - pq][2,6] - benzodioxacyclooctadecin - 13,2′ - [2H]pyran] - 7 - yl - 2,6 - dideoxy - 4 - O - (2,6 - dideoxy - 3 - O - methyl - α - l - arabino - hexopyranosyl) - 3 - O - methyl - α - l - arabino - hexopyranoside)
Molecular Formula: A mixture of Ivermectin Component B1a (C48H74O14) and Ivermectin Component B1b (C47H72O14)
CAS Number: 70288-86-7
Brands: Sklice

Introduction

Pediculicide;1 avermectin derivative.1 5 6 7

Uses for Ivermectin

Pediculosis

Topical treatment of pediculosis capitis (head lice infestation) in adults and children ≥6 months of age.1 2 15

Slideshow: 10 Common Symptoms That Should Never Be Ignored

AAP and others usually recommend topical treatment with OTC preparation of permethrin 1% or pyrethrins with piperonyl butoxide for initial treatment; other topical pediculicides (e.g., malathion 0.5%, benzyl alcohol 5%, spinosad 0.9%) recommended if OTC preparations ineffective or permethrin or pyrethrin resistance suspected.3 15 16 Oral ivermectin recommended as an alternative for infestations not responding to or resistant to topical agents.15 16 17

Ivermectin Dosage and Administration

General

Measures to Avoid Reinfestation and Transmission of Lice

  • To avoid reinfestation or transmission of lice, most experts recommend that clothing, hats, bed linen, and towels worn or used by infested individual during the 2 days prior to treatment be decontaminated (machine-washed in hot water and dried in a hot dryer).1 3 4

  • Items that cannot be laundered can be dry-cleaned or sealed in a plastic bag for 2 weeks.3 4

  • Decontaminate combs, brushes, and hair clips used by infested individual by soaking in hot water (>54°C) for 5–10 minutes.1 3 4

  • Thoroughly vacuum car seats, upholstered furniture, and floors of rooms inhabited by infested individual.3 4 Fumigation of living areas not necessary.3 4

  • Evaluate other family members and close contacts of infested individual and treat if lice infestation present.3 4 Some clinicians suggest treating family members who share a bed with infested individual, even if no live lice found on this family member.3 4 Ideally, treat all infested household members and close contacts at same time.4

  • A fine-toothed or nit comb may be used to remove any remaining nits (eggs) or nit shells from hair.1 3 4 Some clinicians do not consider nit removal necessary since only live lice can be transmitted, but recommend it for aesthetic reasons and to decrease diagnostic confusion and unnecessary retreatment.3 Other clinicians recommend removal of nits (especially those within 1 cm of scalp) to decrease risk of reinfestation since no pediculicide is 100% ovicidal and potentially viable nits may remain on hair after treatment.3 Although many schools will not allow children with nits to attend, AAP and other experts consider these no-nit policies excessive.3

Administration

Topical Administration

Apply topically to scalp and hair as 0.5% lotion.1

For external use only.1 Do not administer orally or intravaginally; do not apply topically to eyes.1

Apply to dry scalp and hair in amount sufficient to thoroughly coat hair and scalp.1 Leave lotion on hair and scalp for 10 minutes, then thoroughly rinse off with warm (not hot) water.1 3 Minimize exposing other areas of skin by performing rinse at a sink (rather than in shower or bath).3

Avoid contact with eyes.1 If contact with eyes occurs, immediately flush with water.1

Available in single-use tube; discard any unused portion.1

Supervise pediatric patients during lotion application; an adult should apply and rinse the lotion for the child.1 (See Inadvertent Ingestion in Pediatric Patients under Cautions.)

Wash hands after applying the lotion.1

Dosage

Pediatric Patients

Pediculosis
Pediculosis Capitis (Head Lice Infestation)
Topical

Infants and children ≥6 months of age: Manufacturer recommends single application.1

Apply to dry hair and scalp in an amount sufficient to completely coat hair and scalp.1 After 10 minutes, thoroughly rinse lotion off with water.1 (See Administration under Dosage and Administration.)

Adults

Pediculosis
Pediculosis Capitis (Head Lice Infestation)
Topical

Manufacturer recommends single application.1

Apply to dry hair and scalp in an amount sufficient to completely coat hair and scalp.1 After 10 minutes, thoroughly rinse lotion off with water.1 (See Administration under Dosage and Administration.)

Prescribing Limits

Pediatric Patients

Pediculosis
Pediculosis Capitis (Head Lice Infestation)
Topical

Infants and children ≥6 months of age: Do not exceed single tube of lotion (120 mL).1

Adults

Pediculosis
Pediculosis Capitis (Head Lice Infestation)
Topical

Do not exceed single tube of lotion (120 mL).1

Special Populations

No special population dosage recommendations.1

Cautions for Ivermectin

Contraindications

  • No known contraindications.1

Warnings/Precautions

Inadvertent Ingestion in Pediatric Patients

To prevent ingestion in pediatric patients, use only under direct supervision of an adult.1 (See Pediatric Use under Cautions.)

Specific Populations

Pregnancy

Category C.1

Lactation

Not known whether distributed into milk after topical application.1 Use with caution in nursing women.1

Pediatric Use

Safety and efficacy not established in infants <6 months of age;1 greater skin surface area to body mass ratio and potentially immature skin barrier in this age group may increase systemic absorption and toxicity.1 Use only in infants and children ≥6 months of age.1

Keep out of the reach of children;1 use only under direct supervision of an adult.1

Geriatric Use

Insufficient experience in adults ≥65 years of age to determine whether geriatric patients respond differently than younger adults.1

Common Adverse Effects

Conjunctivitis, ocular hyperemia, eye irritation, dandruff, dry skin, burning skin sensation.1

Interactions for Ivermectin

No formal drug interaction studies to date.1

Ivermectin Pharmacokinetics

Absorption

Bioavailability

In 20 pediatric patients (6 months to 3 years of age) with head lice infestation, mean peak plasma concentration following single topical application of ivermectin 0.5% lotion was 0.24 ng/mL (lower limit of quantitation 0.05 ng/mL).1 10

Distribution

Extent

Following topical application, not known whether distributed into milk.1

Elimination

Metabolism

Systemically absorbed ivermectin metabolized in liver, principally by CYP3A4, and eliminated almost exclusively in feces.5

Stability

Storage

Topical

Lotion

20–25°C (may be exposed to 15–30°C); do not freeze.1

Actions and Spectrum

  • An avermectin-derivative anthelmintic, pediculicide, and scabicide;1 5 6 7 a macrocyclic lactone similar to macrolide antibacterials but possesses no antibacterial properties.6 7

  • Binds selectively and with high affinity to glutamate-gated chloride ion channels in nerve and muscle cells of invertebrates, leading to increased cell membrane permeability to chloride ions; cellular hyperpolarization ensues, followed by paralysis and death.1 6 8 Also appears to interact with other ligand-gated chloride channels, such as those gated by GABA.1 6

  • Topically applied ivermectin has activity against Pediculus humanus capitis; has shown in vitro activity against a permethrin-resistant strain.11 12

  • Pediculicidal; not ovicidal.3 11 12 Some evidence suggests ivermectin may interfere with louse mouthparts, resulting in impaired feeding in treated lice.12 Topical administration has resulted in death of nearly all newly hatched nymphs and adult lice within 48 hours.11 12

Advice to Patients

  • Importance of following application instructions, including amount of lotion to apply, how long to leave on hair, and how to remove.1

  • Advise patients that the lotion is for topical use on scalp and scalp hair only.1

  • Importance of avoiding contact with eyes; if contact occurs, gently flush eyes with water.1

  • Advise patients that ivermectin 0.5% lotion should not be administered orally.1 If inadvertently ingested, patient should seek immediate medical attention.1

  • Importance of washing hands after application.1

  • Importance of keeping out of reach of children; use on children only under direct supervision of an adult.1

  • Importance of informing clinician of existing dermatologic conditions or sensitivities prior to treatment.1

  • Importance of women informing their clinician if they are or plan to become pregnant or plan to breast-feed.1

  • Importance of informing clinician of existing or contemplated concomitant therapy, including prescription and OTC drugs and dietary or herbal supplements, as well as any concomitant illnesses.1

  • Importance of informing patients of other important precautionary information.1 (See Cautions.)

Preparations

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

Ivermectin

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Topical

Lotion

0.5%

Sklice

Sanofi Pasteur

AHFS DI Essentials. © Copyright, 2004-2014, Selected Revisions August 5, 2013. American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland 20814.

References

1. Sanofi Pasteur Inc. Sklice (ivermectin) lotion 0.5% for topical use prescribing information. Swiftwater, PA; 2012 Feb.

2. Pariser DM, Meinking TL, Bell M et al. Topical 0.5% ivermectin lotion for treatment of head lice. N Engl J Med. 2012; 367:1687-93. [PubMed 23113480]

3. Frankowski BL, Bocchini JA, Council on School Health and Committee on Infectious Diseases. Head lice. Pediatrics. 2010; 126:392-403. [PubMed 20660553]

4. Centers for Disease Control and Prevention. Head lice treatment. From CDC website. Accessed 2013 Mar 1.

5. Merck & Co, Inc. Stromectol (ivermectin) tablets prescribing information. Whitehouse Station, NJ; 2010 May.

6. Roos TC, Alam M, Roos S, et al. Pharmacotherapy of ectoparasitic infections. Drugs. 2001; 61:1067-88. [PubMed 11465870]

7. Ette EI, Thomas WO, Achumba JI. Ivermectin: a long-acting microfilaricidal agent. DICP Ann Pharmacother. 1990; 24:426-33.

8. Burkhart CN. Ivermectin: an assessment of its pharmacology, microbiology and safety. Vet Human Toxicol. 2000; 42:30-5.

10. Hazan L, Berg JE, Bowman JP et al. Pharmacokinetics and safety of 0.5% ivermectin lotion for head louse infestations. Pediatr Dermatol. 2013; 30:323-8. [PubMed 23131185]

11. Strycharz JP, Yoon KS, Clark JM. A new ivermectin formulation topically kills permethrin-resistant human head lice (Anoplura: Pediculidae). J Med Entomol. 2008; 45:75-81. [PubMed 18283945]

12. Strycharz JP, Berge NM, Alves AM et al. Ivermectin acts as a posteclosion nymphicide by reducing blood feeding of human head lice (Anoplura: Pediculidae) that hatched from treated eggs. J Med Entomol. 2011; 48:1174-82. [PubMed 22238876]

15. American Academy of Pediatrics. 2012 Red Book: Report of the Committee on Infectious Diseases. 29th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2012.

16. Anon. Drugs for parasitic infections. Treat Guidel Med Lett. 2010; 8:e1-16.

17. Reviewer comments (personal observations) on Ivermectin 8:08.

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