In a randomized double-blind study, the percentage egg reduction and cure rate after the standard schedule of metrifonate treatment ofSchistosoma haematobium (3 doses of 7.5 mg·kg−1 at two-weekly intervals; A) and an abbreviated regimen (3 doses of 5 mg·kg−1 in one day; B) were compared in five villages in Somalia.
300 patients who were excreting 20 or more eggs ofS. haematobium in 10 ml urine were recruited. The patients were classified according to their home villages and were then, randomly allocated to treatment A or B. They had similar ages, weights and egg output. Each patient received 3 doses of metrifonate and 2 doses of identical appearing placebo. Group A received metrifonate on the 1st, 4th and 5th dosing occasions and placebo on the 2nd and 3rd times. Group B received metrifonate on the 1st, 2nd and 3rd dosing times and placebo on the 4th and 5th times.
Two hundred and one patients were followed up from 1 to 6 months. The remaining 99 (33%) patients either did not complete treatment or were lost during follow up. Egg reduction in the groups 1, 2, 3 and 6 months after treatment were 97, 97, 95 and 93% in Group A and 96, 96, 94 and 92% in Group B (NS). Corresponding cure rates for Group A were 52, 50, 48 and 44%, and in Group B they were 47, 48, 43 and 40% (NS). Seven patients from Group A and 9 from Group B complained of minor side-effects.
Thus, under field conditions abbreviated regimen of metrifonate 5 mg·kg−1 3-times in one day could have as much efficacy and safety as the standard schedule of 3 doses of 7.5 mg·kg−1 at two-weekly intervals.