At present, no universally-accepted effective treatment for cutaneous
gnathostomiasis is available. At the Hospital for Tropical Diseases, Mahidol University,
albendazole 400 mg twice a day for 14 days is commonly prescribed for patients diagnosed with cutaneous
gnathostomiasis. The efficacy of
albendazole to induce outward migration of the parasite was less than or around 20% in 2 studies. Research for alternative, more efficacious treatment, is needed. In this prospective open-labeled study, we assessed the safety of
ivermectin in 20 Thai patients diagnosed with cutaneous
gnathostomiasis.
Ivermectin, one time only, at dosages of 50, 100, 150, or 200 microg/kg bodyweight, was given orally to 4 groups of patients, 5 patients each group. Adverse events were recorded and laboratory tests were obtained before and
after treatment. No serious adverse events occurred in this study. Forty adverse events were possibly related to
ivermectin. The adverse events were malaise (35%),
myalgia (30%), drowsiness (30%),
pruritus (20%),
nausea/
vomiting (20%),
dizziness (15%),
diarrhea (15%), feeling of
shortness of breath (10%), feeling of palpitations (10%),
constipation (5%),
anorexia (5%), and
headache (5%). These adverse events were self-limited and not dose-related. Laboratory abnormalities were found in 3 patients (15%). Transient microscopic
hematuria,
pyuria, and mildly elevated liver
enzymes were found in 1 patient each.
Ivermectin single dose, of 50,100, 150, and 200 microg/kg bodyweight, is considered safe in Thai patients. Future trials of
ivermectin on human
gnathostomiasis may be performed using dosages up to 200 microg/kg bodyweight.