We have carried out an open clinical study in Somalia to evaluate the efficacy and safety of a simplified dosage schedule of metrifonate in the treatment of Schistosoma haematobium infection. The doses used were:
10 mg · kg−1 once daily for 3 days
5 mg · kg−1 thrice daily for one day
7.5 mg · kg−1 thrice daily for one day.
We screened a total of 550 subjects in four villages for egg excretion in urine, and selected patients with more than 200 eggs per 10 ml of urine. In the initial phase of the study eight patients were assigned to each of the three dose schedules. In an extended study 38 additional patients were treated with regimen II which gave the best outcome in the initial study.
Dosage Schedules I and III turned out to be toxic, and none of the patients was treated with all three doses. Adverse effects, such as abdominal colic, nausea, salivation, dizziness, and headache, were seen in almost all the patients in those two groups. Two patients from Group I reported that they fainted within 2 h after the second dose. None of the patients in Group II reported adverse effects.
After 4–6 weeks follow-up, egg reduction was 96–100% for Groups I and II and the cure rate was around 60%.
This study has shown that a shorter course of treatment with metrifonate might be equally effective and safer than the recommended dosage schedule with three doses of 7.5–10 mg · kg−1 fortnightly.
metrifonate schistosomiasis administration and dosage adverse reactions filters