Scabies is a skin infestation caused by tiny mites known as Sarcoptes scabiei, which burrow into the skin to lay eggs. This condition can lead to intense itching and a pimple-like rash. Ivermectin, an anti-parasitic medication, is a widely used and effective treatment option for scabies infestations.
How Ivermectin Targets Scabies
Ivermectin works by specifically targeting the nervous and muscular systems of the Sarcoptes scabiei mites. It binds to glutamate-gated chloride channels in their nerve and muscle cells. This binding increases the cell membrane’s permeability to chloride ions.
The influx of chloride ions causes the mite’s nerve and muscle cells to hyperpolarize, leading to paralysis and ultimately, the death of the parasite. Ivermectin is considered safe for human use because these specific chloride channels are either not present in the central nervous system of mammals or the drug does not readily cross the mammalian blood-brain barrier.
Treatment Protocol for Scabies
Ivermectin for scabies is typically administered as an oral medication, available only by prescription. The standard dosage for treating scabies is 200 micrograms per kilogram of body weight. A common treatment approach involves a single dose, followed by a second dose administered 7 to 14 days later.
The reason for the second dose is that ivermectin does not kill scabies eggs. The delayed second dose helps to eliminate any mites that hatch from eggs laid before the initial treatment. While the medication effectively kills the mites, itching may persist for several days to weeks, as this is often an allergic reaction to the dead mites.
A comprehensive treatment strategy includes treating all close contacts simultaneously to prevent re-infestation. Environmental decontamination is also important. Clothing, bedding, and towels used by the infested person should be machine washed in hot water or sealed in plastic bags for several days to kill any remaining mites.
Important Considerations for Ivermectin Use
Ivermectin generally has mild and temporary side effects. Common reactions can include headache, dizziness, nausea, vomiting, diarrhea, constipation, or muscle and joint pain. Some individuals might experience a temporary worsening of itching or a rash as the mites die.
Certain individuals require special consideration before taking ivermectin. Its safety has not been established for pregnant or breastfeeding women, and it is generally not recommended for use in these groups unless the potential benefits outweigh the risks. Ivermectin can pass into breast milk in low concentrations. The medication is also not recommended for children weighing less than 15 kilograms or under five years of age.
Caution is advised for individuals with liver impairment, as ivermectin is metabolized in the liver. While some cases of ivermectin resistance in scabies mites have been reported, it is not widely prevalent. Treatment failures are often attributed to factors like non-adherence to the treatment protocol, re-infestation, or insufficient dosing rather than true drug resistance. It is always important to consult a healthcare professional for accurate diagnosis and appropriate prescription.