Head lice resistance is pervasive.

Over the past 40 years, several mechanisms for resistance have developed in human head lice rendering anti-parasitic agents ineffective—including Malathion, Lindane and now the most common OTC formulations.1

Neurotoxic agents (pyrethrins, pyrethroids, and DDT) that bind to voltage-sensitive sodium channels (VSSC), are rendered ineffective due to target site insensitivity known as knockdown resistance or kdr – one of the most common mechanisms of resistance in parasites.1

Chemical in lab

Increasing frequency of kdr-type mutations in head lice parallels the decreasing effectiveness of OTC formulations containing permethrin and pyrethroids.1,2

DNA strands

Since the late 1990’s, eight clinical studies demonstrated a declining rate of effectiveness of the permethrin-containing Nix® formulation, which no longer provides a level of effective control.1

Digital image of lice

Dr. J. Marshall Clark, PhD discusses the evidence of continued patterns of resistance and specific gene mutations taking place in head lice infestations.

View an in vitro assessment of knockdown resistance in action1

The three pyrethrin- and pyrethroid-resistant gene mutations are observed in an average of 98% of lice gathered from 48 states1 like these, shown 15 minutes after treatment with Nix® (permethrin 1%) as compared to an untreated group.*

 

Without administration of active agent.

 

Following administration of permethrin 1%.

*Source: Videos created in collaboration with J. Marshal Clark, et al, and the Department of Veterinary Animal Sciences, Molecular Pharmacology, Microbiology, and Biochemistry and Molecular Biology at the University of Massachusetts, Amherst

Nix® is a registered trademark of Prestige Brands, Inc.

 

References:

  1. Gellatly KJ, Krim S,Palenchar DJ, et al. Expansion of the knockdown resistance frequency map for human head lice (phthiraptera: pediculidae) in the United States using quantitative sequencing. Journal of Medical Entomology, 2016:1-7.
  2. Yoon KS, Previte DJ, Hodgdon HE, et al. Knockdown resistence allele frequencies in North American head louse populations. J Med Entomology. 2014;51(2):450-457.

NAT-RRW4-000

Indication
Natroba™ Topical Suspension is a pediculicide indicated for the topical treatment of head lice infestations in patients six (6) months of age and older.

Adjunctive Measures
Natroba™ Topical Suspension should be used in the context of an overall lice management program:

Important Safety Information

Indication
Natroba™ Topical Suspension is a pediculicide indicated for the topical treatment of head lice infestations in patients six (6) months of age and older.

Adjunctive Measures
Natroba™ Topical Suspension should be used in the context of an overall lice management program:
• Wash (in hot water) or dry clean all recently worn clothing, hats, used bedding and towels
• Wash personal care items such as combs, brushes, and hair clips in hot water
• A fine-toothed comb or special nit comb may be used to remove dead lice and nits.

Important Safety Information
Natroba™ Topical Suspension contains benzyl alcohol and is not recommended for use in neonates and infants below the age of 6 months. Systemic exposure to benzyl alcohol has been associated with serious adverse reactions and death in neonates and low birth-weight infants when administered intravenously. Most common adverse events were: application site redness (3%), eye redness (2%) and application site irritation (1%).

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088.