New Options for Eradicating Resistant Head Lice

Marcia L. Buck, Pharm.D., FCCP, FPPAG

Disclosures

Pediatr Pharm. 2012;18(6) 

In This Article

Benzyl Alcohol 5% Lotion

The approval of benzyl alcohol 5% lotion (Ulesfia®, Shionogi Pharma, Inc.) represents the first time this commonly used pharmaceutical preservative has been utilized as an active ingredient. Benzyl alcohol kills lice by inhibiting their ability to close their respiratory spiracles, causing the lice to asphyxiate. It does not have ovicidal activity. The lotion vehicle contains water, mineral oil, sorbitan monooleate, polysorbate 80, carbomer 934P, and trolamine as inactive ingredients.[3]

Benzyl alcohol 5% lotion was studied in 628 patients 6 months of age and older prior to approval. Three phase II studies were conducted to determine optimal dose and duration of lotion application. Two multicenter, randomized, vehicle-controlled phase III studies were conducted in patients with head lice infestation. The primary endpoint was the proportion of subjects who were lice-free 14 days after their last treatment. In the first study, 76.2% of subjects in the group receiving treatment with the benzyl alcohol 5% lotion were lice-free, compared to 4.8% of those treated with the vehicle alone. In the second study, 75% of the active treatment group were lice-free, compared to 26.2% of the group given the vehicle alone. An open-label extension trial was conducted after the two controlled trials. There were 128 subjects enrolled in this trial, including 81 treatment failures from the previous trials (68 of whom had received only the vehicle) and 47 new subjects. Fourteen days after the second treatment, 96 subjects (75%) were lice-free.[3,6]

Benzyl alcohol 5% lotion should be applied to dry hair, saturating the hair and scalp. The manufacturer includes guidelines for the amount of lotion to be applied based on the patient's hair length in the patient information leaflet contained in the package. The lotion is available in 4 and 8-ounce bottles, and the volume to be applied ranges from 4 ounces for short hair (0-2 inches) to 48 ounces for long hair (over 22 inches in length). After 10 minutes, the lotion should be rinsed off with water. The hair may be shampooed immediately after the lotion has been rinsed off. Use of a small-tooth comb to remove nits is recommended. If lice are still present, the treatment may be repeated in 7 days.[3]

As with all topical lice treatments, care should be taken to avoid getting the product in the mouth or eyes. Adverse effect data for benzyl alcohol 5% lotion were pooled from two randomized, multicenter, vehicle-controlled clinical trials and one open-label study. The most commonly reported adverse effects were pruritus (occurring in 12% of patients), erythema (10%), pyoderma (7%), or ocular irritation (6%). Less common reactions included application site dryness, excoriation, paresthesia, or thermal burn (all < 1%). Contact dermatitis has been reported in a small number of patients using this product.[3]

There is minimal systemic absorption after topical administration. In a study of 19 children ranging in age from 6 months to 4 years, a 30 minute application of the lotion resulted in measurable benzyl alcohol levels in 4 of the patients (21%). Concentrations ranged from 1.63 to 2.99 mcg/mL.[3,6]

The use of benzyl alcohol 5% lotion is restricted to patients 6 months of age and older. Use in younger infants, particularly neonates or premature infants, could produce toxic serum concentrations as the result of impaired clearance stemming from reduced levels of alcohol dehydrogenase. Toxicity resulting from administration of IV medications containing benzyl alcohol in infants, referred to as "gasping syndrome," was first noted in the 1980's. The syndrome consists of severe metabolic acidosis, a gasping respiratory pattern, hypotension, central nervous system depression, seizures, intraventricular haemorrhage, and death. Although the potential systemic exposure following a single 10 minute application of the 5% lotion is significantly lower than that reported in cases of gasping syndrome, there is enough reason for concern that the product has not been tested in and is not indicated for use in infants younger than 6 months.[3,7]

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