Background: Scabies is a common parasitic infestation and is very difficult to eradicate from institutions. Ivermectin is used extensively thanks to its efficacy and ease of use through oral administration; it was approved for the treatment of scabies in humans in 2001 in France. Most of the adverse effects noted with this drug have been seen during treatment of onchocerciasis and other filarial disease, but they are rare in the treatment of scabies. We report side effects with ivermectin in two elderly patients with scabies.
Cases report: A 72-year-old man was referred for scabies and was treated with benzyl benzoate (Ascabiol) and ivermectin (200 microg/kg) in a single dose. Two days later, the patient presented abdominal pain and nausea. Laboratory tests revealed cytolysis tests for other causes of hepatitis were negative. Within two weeks, liver function had returned to normal. Hepatitis due to ivermectin was diagnosed. An 86-year-old woman hospitalised for scabies was treated with benzyl benzoate and a single dose of ivermectin (200 microg/kg). She developed sinus tachycardia and asthma 3 days later. Screening for embolic, cardiac and infectious origins was found. Toxicity of ivermectin was suspected.
Discussion: Since the introduction of ivermectin for the treatment of scabies, reports of adverse events are rare although this drug can cause cardiac dysfunction and liver disease in other indications. In our cases, the causal relationship with ivermectin is probable and care must be taken, particularly in the elderly, the population in which this drug is probably most widely prescribed.