"Scientists at the National Institutes of Health report they have discovered in mouse studies that a small molecule released in the spinal cord triggers a process that is later experienced in the brain as the sensation of itch.
Mechanism of Action
Ivermectin, a member of the avermectin class, causes death of parasites, primarily through binding selectively and with high affinity to glutamate-gated chloride channels, which occur in invertebrate nerve and muscle cells. This leads to an increase in the permeability of the cell membrane to chloride ions with hyperpolarization of the nerve or muscle cell, resulting in paralysis and death of the parasite. Compounds of this class may also interact with other ligand-gated chloride channels, such as those gated by the neurotransmitter gamma-aminobutyric acid (GABA). The selective activity of compounds of this class is attributable to the fact that some mammals do not have glutamate-gated chloride channels, the avermectins have a low affinity for mammalian ligand-gated chloride channels, and ivermectin does not readily cross the blood-brain barrier in humans.
The pharmacodynamics of SKLICE Lotion are unknown.
The absorption of ivermectin from SKLICE Lotion was evaluated in a clinical study in subjects aged from 6 months to 3 years. This study evaluated pharmacokinetics in 20 lice infested subjects, and 13 of these subjects weighed 15 kg or less (overall weight range 8.5-23.9 kg). All enrolled subjects received a single treatment with SKLICE Lotion. The systemic ivermectin exposure was evaluated using an assay with a lower limit of quantitation of 0.05 ng/mL. The mean (± standard deviation) plasma maximum concentration (Cmax) and area under the concentration-time curve from 0 to time of last measurable concentration (AUC0-tlast) were 0.24 ±0.23 ng/ml and 6.7 ± 11.2 hr*ng/ml respectively. These levels are much lower than those observed following oral administration of 165 meg/kg dose of ivermectin.
Two identical multi-center, randomized, double-blind, vehicle-controlled studies were conducted in subjects 6 months of age and older with head lice infestation. All subjects received a single application of either SKLICE Lotion or vehicle control with instructions not to use a nit comb. For the evaluation of efficacy, the youngest subject from each household was considered to be the index subject of the household (N=289). Other enrolled infested household members received the same treatment as the youngest subject, and were evaluated for all safety parameters [see ADVERSE REACTIONS].
The primary efficacy was assessed as the proportion of index subjects who were free of live lice at day 2 and through day 8 to the final evaluation 14 (+2) days following a single application. Subjects with live lice present at any time up to the final evaluation were considered treatment failures. Table 1 contains the proportion of subjects who were free of live lice in each of the two trials.
Table 1: Proportion of Subjects Free of Live Lice 14 Days
| SKLICE Lotion
|Study 1||16.2% (12/74)||76.1% (54/71)|
|Study 2||18.9% (14/74)||7 1.4% (50/70)|
Last reviewed on RxList: 2/22/2012
This monograph has been modified to include the generic and brand name in many instances.
Additional Sklice Information
- Sklice Drug Interactions Center: ivermectin top
- Sklice Side Effects Center
- Sklice FDA Approved Prescribing Information including Dosage
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